Environmental Issues — BIOLOGY STD 12 Science — Question

List any four factors which may lead to loss of biodiversity.

What are the problems expected from population explosion?

What is Biopiracy? Explain it with respect to Turmeric.

Keeping beehives in crop fields has several advantages.

Of the eight nuclei formed in the embryo sac, six become organised into cells.

1. What term is given to the other two nuclei?
2. Name the cell in which they are present.

Classify the following contraceptive measures into different methods of birth control.

1. Saheli.
2. Tubectomy.
3. Vasectomy.
4. Condoms.
5. Diaphragms.
6. Cervical caps.

A moss plant produces a large number of antherozoids but relatively only a few egg cells. Why?
OR
Why do moss plants produce very large number of male gametes? Provide one reason. What are these gametes called?

Name the process of formation of male gametes in flowering plants.

What are the advantages of natural methods of contraception over artificial methods?

Name the two most commonly employed hosts and the vectors for human gene cloning.