0:02 So hello good evening all of you. So I hope that you all must have used your Sunday to revise all the concept which we have done in the week days and I also expect that all of you now must be having your NCERT and you all must have tried to read these uh the NCERT. So in this chapter we have already started with plant kingdom. Yes. Hello all of you. So hello uh Alia, Ganesh, sweetie, shake. So hello all of you. So if uh my voice is clear just give me a thumbs up so that I can start with a class.
0:48 So now as we have started with a plant kingdom and here we have already covered the algae. We have also covered the bio uh we have also covered the bryophites. In the last class we have seen what are the difference between liver warts and mosses. All that we have done we have done some question based on that. Now today we are going to start with a very interesting and uh a very interesting uh plant category. So just let's first see some of the diagram. Can you identify this plant? So this is one of the plant as you can see now another diagram. See this plant. Can you identify this plant?
1:35 Now if if if anyone can identify this plant just write it in the chat box which plant it is and we are going to study about this plant today. So now this plant actually it is a teridopites as many of you are mentioning correctly they are terrify. So today our topic is to study a a category of plant that is teridophy. We have already covered the algae. We have already covered bryophites. Now we are we will be seeing teridophy. So what is their special in terophy? Now one thing if you see in all these three diagrams what is the most prominent thing you
2:21 will find that they all these all plants are leafy structure. So leaf are dominating these plants. If you see in plant other than leaf, you don't see any other thing. Okay. So many of you are ex uh are guessing it as mimosa pudika. Touch me not plant. No. So this is not a touch me not plant. Mimosa pudika is a angioper that we will see later. So this is a terteridopyte. This is a terterodite in most of the uh it is basically ornamental plants which are used in offices and in gardens. So so this is teridophyte and you can see it is mostly dominated by leafy structure.
3:07 Most of the part of the plant is leafy in nature. So again if you see this one so these plants teridophide since they are leafy in nature. So they have basically three types of leaf. They have three types of leaf. Three types of leaf. Now let's first understand. As you can see this is also a leaf. This is also a leaf. But can you distinguish? Can you tell me which is one leaf? If you see these are all having very small leaf. These are small leaves and since they are very small
3:54 leaves as you can see these are the branches and very tiny leaves are present in these plant. So they are called microills. Now till now now now onward wherever you get the term fill right wherever you get the term fill always consider that it is talking about leaf right so microfill means small leaf. So some of the plant some of the teridophites can have small leaf. And here remember the example the example is the example of small leaf is cella
4:39 genella. Cellagenella is an example. Now this you remember question is asked which of the following plant will have small leaf or microfills and that is celaginella. So small leaf. So other plants may also have large leaf. As you can see here you can distinctly see each of the leaf. So these are called large leaf. So they are large leaves and these large leaves are called they are called macrofills. They are called macrofils. They are usually present in ferns. Now you can recognize you all must have
5:25 heard about ferns right? So ferns have macrofield that is large leaf. So these are the two types of leaf. Now the third special type of leaf which is present in teridophite is this. Now what is special in this leaf? See it very carefully. It is not just leaf. There is some brown small spherical. All of you can observe. Just see carefully. If you see these leaves are having small brown structure on the leaf. Right? So these are special type of leaf and they are called sporofll. They are called sporophil or you can also simply call them
6:11 reproductive leaf. Reproductive leaf. So the first two leaf the microfill and the macrofill these two types of leaves they were vegetative in nature. Their role was photosynthesis just a typical role of leaf. But here they are reproductive leaf. Now you will be wondered sir how what is reproductive leaf? I haven't heard about leaf which is reproductive. Right? How can leaf be reproductive? So yes these teridophides do not have flower. They don't have flower. So who will do which what is the part which will do reproduction? So that is a
6:56 sporofil. Now as you can see here these there are series of sporophil there are many leaves and each leaves are having sporangia these structure small are called sporangia I will explain. So I will if I draw a simplified structure see this is leaf. It is something like this isn't it? It is something like this. So several leaves are together forming a structure and that structure is called cone. Remember cone or strobili. So now from here we we are learning many new things. So first thing what we learn here is that teridopite is
7:44 a category of plant in which leaves are dominant. Fine. So if leaves are dominant there will be many types of leaf. So first two type of leaf microfill and macrofill small leaf and large leaf are the vegetative structure. The third type of leaf is the reproductive leaf also called as sporofll. Sporofil several sporofll will come together to form cone or strobili. So repeat with me the reproductive structure of teridoite is called cone. Cone is also called strobili. Strobili or cone is made up of it is made up of
8:30 several sporophils. Now what is special about a sporophil? So individually if you see so sporofll is a leaf which has a unique structure on it and that structure is called it is something like this. Let's say this is the structure and this structure is called sporangia. This structure is called sporangia. I'm writing it here. Note it down. It is called sporangia. This sporangia will help in the formation later on we will see it will help in the formation of spore. it
9:15 will help in the formation of spore. So now we are seeing very beautiful kind of flower which is very commonly used as an ornamental plant because it has leafy structure and we know that leafy plants are used very oftenly for ornamental purpose in our home in our offices in our garden. So this is the plant. Now although they are ornamental plant but are they flowering plant? No, they are not flowering plant. So now after having idea about these three types of leaf, let's move ahead. Now if we see some general character of this terteridoite. So teridophyte will be more advanced as compared to bryophites. Now here they
10:03 are the first terrestrial plant to possess vascular tissue. See till now neither algae nor bryophy has vascular tissue these xylem and phm that is the vascular tissue is present only in terophy. So question tell me which plant for the first time vascular tissue developed. So the answer will be vascular tissue developed for the first time in teroyes. What is vascular tissue? xyllem and phm together are called vascular tissue. Now this is also known as because they are vascular and they are nonflowering. They
10:51 are vascular and they are non-flowering. So they are called as vascular cryptograms. Question will be asked which is vascular cryptogram. So vascular cryptogam is teridophide. Then seedless vascular plant. Now here although vascular bundle develop but they are seedless still seed is not present. Still seed is not seed is not present in algae. Seed is not present in bryophy. Seed is not present in teridophy. Then in this case the dominant phase is a sporopy. Now question all of you about 300 student connected right now just tell me what is this is a question from last
11:40 class. I will I will like to see how many of you can recall this plant recall this part. First question is what is the dominant phase in the life cycle of bryophite? You have 20 seconds to answer. What is the dominant phase of bryophite? What is the dominant phase of bryophite? All of you use your chat box only to give answer. No communication among yourself. Yes, first. Let me see who answer first. What is the dominant phase of bryophite? Very good. Khalil has given the answer. Tanish right. Thunder Nirj
12:25 very good. Gamito ready. Yes. Very good. So no. So so I have got gametophite as the answer. Very good. So most of you recall that bryophite the dominant phase is gamtophite. Right? Now here see here the dominant phase is sporofy. Remember another important point gamtote is hloid or deployed. Gamto is hloid or deployed. So gamitoyite is hloid. Gamito is n. Now here sporopy. So in case of teridopyte the sporopy is the dominant phase and they are found in cool damp shady places
13:12 or sometime in sandy soil condition. So still they are found in terrestrial plant but still they need cool damp shady places. In desert-like condition they will not be found. As you can see such fern type of plant as I have shown here they are mostly found in the cool damp and shady places not in a very hot and desert-like condition. Now so here is the question. Here is the question. I am putting the timer on. I expect all of you to answer it fast. So you all have 20 second to answer it. So this is the question. Terido are the first plant
13:58 to have. You all have 20 second to answer it. Teridoes are the first plant to have. Do terido have seed? Terido don't have seed. So time is up. I expect all of you to answer. Write in the chat box. Teridoi don't have seed. Teridoi don't have flower. Teridoi don't have fruit. They are the first plant to be vascular tissue. What is vascular tissue? Xyle and phm together are called vascular tissue. Now next question. Again you have 20 seconds. So now again you have 20
14:44 seconds. Microfill just I have explained what is microfill. Microfill are small leaves found in where are microfill found? Small leaf found in just I have given the example with diagram. Yes, I can see Vijay giving answer B. Khalil giving answer B. Pravin Bat Aaya very good. So B answer is coming means you all were attentive when I mentioned. So yes it is correct. Cellinella have microfils. Cellagenella have microfils.
15:30 Now another additional question here. If I say megapill, which one has megapill? So fern is mega or macrofill means large leaf is present in ferns. Right? So that is it for this section. Now let's move ahead. So I can see most of you are answering but still I can see some of you are not answering and no need to write something else in the chat other than the answer. Now let's move ahead. The leaf of ferns are The leaf of ferns are what are the leaf of ferns? Just I have explained the leaf of ferns
16:17 are out of which which is the category of leaf of fern? Waiting for the answer. Sixth. Okay, I can see sik bashkar pushpa puja abi rahan. So most of you are writing A as the answer H. So here the leaf of ferns R okay B H now I am getting maximum as B some of you are writing as C fine so see leaf of fern are what we say macrofill leaf of ferns are macrofll macrofill means large leaf right so as
17:06 you can see they are compound round and large leaf. So correct answer for sixth will be B. As I can see many of you have answered B correctly. Yes, Sanvi correct. Lakshia Prince right. Daniel Yeshuant Shik Lakshmi very good. Deepipika very good. You all have answered correctly. So this is about the leaves. Now if we further move about other character now you just stay away from the chat box. Let's cover this theory and then again I will ask question then you can answer it. Now vascular tissue we have seen that they
17:52 are the first plant to have vascular tissue. So vascular tissue is welldeveloped that is they have xylem and phm. But remember vessel is not present in the xyllem. See later on we will study that xyllem has four part right? Zyllem and uh many of you have already studied it in your 10th class that xylem have four parts vessel xyllem fiber and xylem paranya. This we will study in detail in
18:40 the anatomy of plant chapter. So out of these four component vessel is absent here. So vessel is absent. So that's why everything is present except vessel. Reproduction. So sexual reproduction take place via spore formation. No seed is there. And where is this spore formed? Spore is formed inside sporangia. And where is this sporangia present? Sporangia is present in the sporofil. And where is this sporophil present? It is present in the cone. Right? So cone is the largest part. Cone
19:25 has a sporophil. Sporophil has sporenia and sporangia form. Spore. Spore take part in the sexual reproduction as it is given here. Spore are produced on sporenia which is present on the sporofll. Is this point clear? Now let's move ahead. So this is a life cycle of terodophy. So let's see. So if I will make it very simple so that you understand it in a better way. First of all, just as we have discussed in bryophite that the life cycle will be divided into diplomic that is 2n and hepllic that is n. So heplontic will be called as the
20:13 gamitoic generation and the hep diplomic will be called as sporofitic generation. Clear? Now this is the plant. This is the terterodidophyte. So teridophyte mainly has leaf. We have already seen that in reproduction which leaf will take part sporophil. So let's say this is the sporophil. Now sporofll will produce spore. Now here you as you can see here spore is there sporangium is the circular structure which will produce spore and that spore will germinate and give rise to young gamitoy. Now this
21:02 young gamtote is called prothalus. Note it down very important the young gamto of question is asked the gamto of terido is called. So the answer is prothalus. Prothalus is the gamtophite of teridophy. Now this gamtote will have two part. Anthetherredium which is the male sex organ. Argonium which is the female sex organ. Anthetheridium will form male gamut. Argonium will form female gamut which will fertilize and produce zygote. and zygote will develop into embryo which develop into the sporopy. Now this I will also write it
21:51 in a flowchart form. Right? Flowchart form. I will write it here so that you understand in a better way and you can take the screenshot from here. See first thing teridophyte. So let's consider teridophyte. So in case of teridophyte what is the main body? So it is sporofite. Now sporopy will have sporof sporofll basically this is present in cone all of you once I draw it you can take a screenshot of it or if you are noting it down note it down into your notebook. So sporophil cone. Now
22:38 sporofll will have sporenia. Sporophil has sporenia. See cone has a sporofil. Sporophil has sporenia. Sporenia has spore mother cell. Spore mother cell will undergo miosis. Miosis. And it form spore. Now this spore will be hloid. This is deployed. Miosis all of you must have studied in cell division. Miosis is called reductional division. It convert 2n into n. Now this spore this spore will germinate and this
23:25 spore will form gamtote. This gamitoy is called it is called prothalus. Prothalus. Now this gito will have male organ and this male organ is called anthetheria. Antheia and it also form the female organ. Female organ is called archonia. Arionia. Now this ariggonia will produce egg. Anthetheridia will produce it will produce male
24:11 gamut. It will produce male gamut. They both will fuse together to form zygote. Now here water is required. Yes. Here also water is required and then zygote will develop into embryo which will develop into sporofi now. So let's see here very important first of all you if you want you can take the screenshot at this point the table is completed the table is completed but let me add few more points here see in between in between this so this is the point now here everything is deployed
25:00 and here everything here Everything is hloid and here everything is deployed. So this is representing the sporofitic generation and this is representing the gamtophitic generation. Right? Now here the game is also photosynthetic. Now remember in the last class what I said if if any part is photosynthetic it do not depend on other for food. So here gamitophy is photosynthetic sporopy is also photosynthetic both are photosynthetic. So now you can take the screenshot all of you take the screenshot I'm giving
25:46 you few second take the screenshot. Okay. So now so this life cycle once again I'll repeat let let me repeat this. So teridophyte the main plant body is sporopy. This sporopy is photosynthetic. Sporopy has a special type of leaf called a sporophil which has a sporangia. Inside the sporenia is a spore mother cell inside and this spore mother cell undergo miosis to form a spore. Spore germinate and develop into gametophite. The gamitoy can have male organ, female organ. The male organ
26:33 is called antheridia which form male gamut and female organ which is called archonia form the egg. The male gamut and egg will fuse together to form zygote. zygote develop into embryo and embryo form the sporopy. So this is the whole life cycle of teridophile which is very very important very very important. So now let's move ahead here remember both gtoyte and sporopy are photosynthetic. So now question who is dependent on whom? Is a sporofy dependent on gamtophite or gamitoy dependent on sporopy? So because both are
27:21 photosynthetic. So nobody is dependent on anybody means both sporopy and gtoyte are independent of each other. What you will say in teridophyte both gametophite and sporopy are independent of each other that you can note it down. So here now whatever life cycle here we have seen here I have put it in the form of text. So let let's read that now you will understand show alternation of generation means what gtoyte and gamtoic and sporopitic these are the
28:06 two generation right so yes both are present now dominant phase is sporofy which produce spore by meiosis we have already seen see it produces spore by Miosis. Then spore germinate into gametophite. See here spore germinate into gametophite. So spore germinate into gamtoyte and it is called proththealus. So is it called proththealus? Yes it is called prothelalus. Then it is a small green and photosynthetic. So is it photosynthetic? Yes, it is photosynthetic in nature. Prothalus is
28:52 independent because it is photosynthetic. It is independent and it has anidia which is the male organ and ariggonia which is the female organ. Do they need water for fertilization? Yes, they require water for fertilization. And then gradually the zygote develop into new sporofite. The zygote develop into new sporopyte. As you can see here they form zygote and zygote develop into sporopy. So this life cycle I hope I expect all of you that it is very much clear. If it is clear give me a double thumbs up. If it is clear then I will proceed forward. Right? These life cycle are very
29:39 important and trust me when if you have your elder brother or sister just go and ask tell me the life cycle of teridophite tell me the life cycle of bryophyte they will find very difficult to explain it because you if you don't focus on the life cycle in a better way then it will be very confusing so as I can see many thumbs up are here. Very good. So now I guess that you all understood this well. Very good. Very good. So now let's move ahead. Let's move ahead. So let me check how many of you have understood. I can see many thumbs up. So in the same way can you answer questions. So here is the
30:26 question. In tero fight the dominant phase of life cycle. Now all of you need to answer. Approximately six uh 300 of you are connected. So I want all of you to answer. So let me see who answer first. In terophide the dominant phase of life cycle is so thunder has given the first answer. B Sakuntala very good. Manoj Puja Lakshia very good. Pinky, Jashwant, Tanushri, Shik. Okay. So, all of you are giving answer B. All of you are giving answer B. Very good. Very good. Means
31:12 you understood the life cycle in terophy. The dominant phase of life cycle is sporopy. Now tell me is sporofy. So if I say this statement, sporofite is photosynthetic. I'm writing it. Sporite is photosynthetic. Photo synthetic. Tell me is it true or false? Just write true or false in the comment. Sporofite is photosynthetic. Is it true or false? Just write T or F so that I can see. Just write true or
31:57 false. Yes. So I can see sudha very good true h tanushri puja tjasri vijay. So sporofite is photosynthetic. Both in fact I can also write this statement that both sporopy and gito both sporopyte and gimtote is phototosynthetic photoynthetic. So this is correct statement now. So let's move ahead now. Next question. The gimtoight of a
32:43 terteridoite is called. Again very simple question. The gamtopite of terido is called. We have seen it just in the life cycle. Just in the life cycle I have seen the gimito of teridophyte is called is it called risoid? Is it called cone? Is it called thalus? Is it called prothalus? H. So I am getting the answer. Basar, Tanish, Lakshia, all of you are giving answer A. Okay. Very good. Shik, Yashwant, Rohit, Puja, Bhan, very good. So all of you are giving answer A means
33:30 you understood it well. The gimito of teridoite is called prothalus. Now one googly question. So this is a googly question. Let me see how many of you answer. Now if I say prothalus prothalus do not have prothalus do not have true root stem and leaf. Prothalus do not have true root stem and leaf. True or false? Now this is a googly question. I will
34:16 explain the answer but first I want you to answer it. Prothalus. See the answer lies in this term only. It is prothalus. Talus word. Have we seen in the last class? What is thalus right? Again I'm getting answer. Very good. So now you all have understood the hint prothalus. Right? So here word is thalus. So thalus will never have true root, stem and leaf. So prothalus do not have true root, stem and leaf. Now another statement I'm going to write and there also you have to say true false. If I
35:02 say teridoite, teridophite have true root, stem and leaf. True root, stem and leaf. Now tell me is it true or false? Terido have true root, stem and leaf. True or false? Okay. So let me see who who answered it for the first time now. So I think I am getting some answer as true. Okay. True false true false mix is there. Okay. Many false answer are also
35:49 there. Okay. So there is a mix true false here. There is a mix true false here. So let me explain. I was knowing that you will have some amount of confusion here. See now till this point you all know that teridophyte has two stage. One stage is gamtophy which is called prothalus. Now it is clear prothalus do not have root stem and leaf. Another stage of teridophyte is the sporopy which is the dominant. Right? So sporofite or teridophite have true root stem leaf. This is correct right. So remember teridoite for the first time have true root stem and leaf.
36:36 True root stem and leaf develop for the first time in teridophite but gito of teridophite don't have true root stem and leaf. I guess that now you it is very much clear that here in the life cycle this sporofite it has true root stem and leaf but gito they have thalus body means no true root and root leaf and stem. So now well done very good all of you are doing great. So now again the same life cycle just in a different way. See this is the
37:23 sporopy which has true root. So here will be the root stem and leaf is present although dominated by leaf. Then here it form spore. Spore germinate and form gameite. Gameight is proalus. Now here you will see here no root stem and leaf as you can clearly see here but they have this root like structure called risoids. Remember risoids is present in if I ask you this question answer it quickly. Risoid is present in sporopy or gamitoite. Question is
38:10 this risoid is present in right sporofite S for sporopy and G for gito. So write down S or G risoid is present in sporofite or gito. You don't just have to you just have to write S or G. Fine. So I can see sporophy gimito sporophy gimito gito sporophyte. Okay. So mix answer is coming. Now see here what I have labeled risoid. Risoid is present in gtoyight.
38:59 See risoid in last class we have seen risoid is a root like structure. Ryoid is a root like structure. So risoid is present in gamtote. So risoid is present in gamtopite because sporofite will have its own true root. Sporophyte will have its own true root. They don't need risoid. Ryzoid is present in proalus and then you see male gamut female game form zygote and it develop into spor five. Now so here one new term we are going to see and that is also very important. It is called homospori and
39:47 versus hetrospori. See most of the bryopight form only one spore only one spore. So that's why they are called as homosporus. Right? Repeat it with me. Most of the teridophites are homospor. But if I say all the teridopyes are homosperous then it is wrong. Most of them are homosperous. Few are heterosporus. And two example is given which you have to remember and that is celagenella and salvinia. Remember very common asked question in neat that give the example of
40:34 hetrosporus give the example of hetrosporus teridophite. So here two type of spores are present and these are called microspor that is male spore and megaspore that is female spore. So again I will give you two statement. First statement just write right or true or false. First statement if I say all teridopites are homosperous. True or false? All teridopites are homospor. So it is false right? It is false because there are few heterosporus also. Now if I say teridoes are both homosporus and
41:22 heterosporus. Is it true or false? Terido are both homosperous and heterosporus. Now this statement is right. Yes they are homosphorus and heterosporus. Another statement if I say most of the terterodidoes are homosperous. This is also right. And if I say few of the teridopites are heterosporus, this is also right. Understood? So few of the teridoes are heterosporus. Terido can be homosperous or heterosporus and most of the teridopyes are homospor. So these are the point. Now heterospori. Now till here we see that there is no seed in
42:09 territo there is no seed but due to heterospori first time hetrospori developed here. So because of that the evolution of seed will start. Although seed do not came here but evolution started. Now if I ask you this question, for the first time heterospori was observed in which plant? For the first time heterospori was observed in so it is in terite. See teridophite a lot of thing occurred for the first time. A lot of thing occurred for the first time. For the first time for the first time. True root stem and
42:58 leaf for the first time. For the first time vascular bundle means xyllem and phm xyllem and phm and also for the first time hetrospor developed. Hetrospori developed just before it. Bryophytes. If I say bryophites. So they are homospor or heterosporus. Tell me the answer. Bryopites are homosperous or heterosporus. So all bryophites are
43:44 homospor. all are homosperous because heterospori developed for the first time in teridophile. So this point is also very much clear. So now question heterospori is seen in. So if you understood it now let's see some of the question very important question. So here heterospori is seen in just we have seen two example for heterospori. So you all have 10 second to answer this. 10 seconds. Hetrospori means two types of spore.
44:30 Microspor and megaspore. Two type of spore it is found in. Yes. So correct answer. Cellaginella. Cellagenella and salvinia. Remember celagenella and selvinia are the two example of hetrosporus hetrosporus teridophide. Now these are some of the example of teridophide like these are some of the categories in which these are the examples. So remember cilopsida, lyopsida, swenopsida, teropsida, cilagenella we have already seen as an example. Celotum, lyopodium, equisetum,
45:17 dryopteris, terrace andum. This group is called fern. Which of the following is fern? So it is teropida which is called fern. Inquisitum it is also called walking fern because it move from one place to another place. So it is called walking fern. Clear? Now question. So here you can see the diagram. This one is this one is celagenilla. This one is equism. This one is fern and this one is salvinia. So here cella genella
46:03 equisetum equisetum this is firm this is diagram taken from your NCERTT and this is salvinia many time in neat they give you a question and then they ask you identify the plant identify the plant so this way you can identify now question which of the following is not a tero fight not a terrio fight. So just we have seen some example. Let me check how many of you have that photographic memory. Just in a flash how many of you can answer. Okay. So I'm waiting for the answer. Which of the following is not a terrio fight? Not a terrio fight. Let me see who answer first. Yes. So Thunder has
46:49 given first answer B. Vijay Khalil. Best DMR. B. Okay. An Aish. Okay. Very good. It seems that you all have a wonderful memory. Puja, Tanish, Ashwin. Very good. So, cycus we have just seen. Celotum is also of teridophide. Inquisetum, walking fun, lyopodium all are example here we have seen. And cycus. Cycus. We will see. Cycus is a gymnosperm more advanced plant. Now last class I have told about assertion reason question. So every day we will have at least one assertion reason question. Today I have prepared two for you. Now you have 20 seconds to
47:36 answer this. You have 20 seconds to answer it. So I have started the timer. Now think and you answer. Think and answer. So first assertion says that terido fight are considered the first vascular plant. So this is yes they are the first vascular plant. It is true they have welldeveloped xylem and phm for conduction of water and food. This is also correct. So does this explain it correctly? So the answer is yes they are
48:23 vascular because they have xyllem and phen. So the correct answer will be a very good sram wankes Ishwar. Very good. Very good. So a is the right answer. Now next question. Last one. Last one for the class today. Cellagenella exhibit hetrospori. True or false? Yes. Cellaginella exhibit heterosporate. It produces morphologically similar spore. Now reason is correct or wrong? Reason is correct or wrong. So heterospori means similar spore or different spore. Homospori produce similar spore.
49:10 So this is wrong. So what we will go for? Assertion is true and reason is false. So see here assertion is true but reason is false. So here the correct answer will be C. Yes, very good. Many of you are giving right answer. So C is the right answer over here. So today we will stop the class here. All of you have participated. So thank you all of you. All of you are doing wonder, wonderful, very good. Very good. So answers are coming. So all of you are participating also. Great. So in this way you will learn a lot and ultimately your botney will become very strong and know and keep it in mind. Usually
49:58 student struggle in botney because these are the topic which are very difficult for them to keep it in mind and from beginning if you are attentive it will be very easy. Okay. So just go back revise and enjoy. Thank you all of you.
