Q1 of 32 Page 204

Draw a neat, labelled diagram of a mature angiosperm, embryo sac.Mention the role of synergids.

OR


Enumerate and describe any five reasons for introducing sex education to school-going children.


Role of synergid:

Synergids consist of filliform apparatus which directs the growth of pollen tube into the embryo sac by secreting some chemical substances.


As the pollen tube enters the synergid, it starts to degenerate.



OR


a) Children need to be prepared mentally for the upcoming body changes due to arrival of adolescence.


b) Sex related issues like STDs, unwanted pregnancies, MTP must be taught.


c) Students are needed to be given classes on sex education, in order to break the taboo related with reproductive health.


d) School students need to be counselled about different aspects of adolescences i.e. related problems and its solutions.


e) Children are needed to be made aware of the importance of habit of cleanliness and hygiene.


More from this chapter

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6

What is Bt toxin? Name an organism that produces it? How has man exploited it?

 7

Discuss in detail how RNA can be used to silence specific genes.

 2

a. In humans, males are heterogametic and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic?

b. Who determines the sex of an unborn child? Mention whether temperature has a role in sex determination.


OR


Give an account of post transcriptional modifications of a eukaryotic mRNA with diagramatic representation


 3

Observe the diagram given below and answer the following.


a. Which biome shows maximum range of annual precipitation?


b. Which biome shows maximum range of annual temperature?


c. Give range of mean annual temperature by corniferous forest


d. Give range of mean annual precipitation by temperate forest


e. Which biome has lowest mean annual temperature?


OR


Every year in winter Siberian cranes migrate from Russia to India forbreeding. In the year 2006, a survey was done which has the values in the given equation


N(t+1) = Nt+ {(B+I)–(D+E)} as follows


N(t+1) = 1200 + {(600+700)–(200+800)}


On the basis of above answer the followings


a. Natality rate


b. Mortality rate


c. Number of cranes immigrated


d. Number of cranes emigrated


e. Population of cranes in India in year 2006.