Reproductive Health — BIOLOGY STD 12 Science — Question

How are assisted reproductive technologies helpful to humans? How are ZIFT and GIFT different from intrauterine transfers? Explain.

List any two types of IUDs that are available for human females and state their mode of action.

Which part of the blastula is destinated to form germ layers of the developing embryo in humans?

"Post-industrialization, the population of melanised moth increased in England at the expense of white-winged moths." Provide explanations.

DNA being hydrophilic, cannot pass through the cell membrane of a host cell. Explain how the recombinant DNA gets introduced into the host cellto transform the latter.

Why do all the fresh water organisms have contractile vacuoles whereas majority of marine organisms lack them?

In a sea shore, the benthic animals live in sandy, muddy and rocky substrata and accordingly developed the following adaptations.

1. Burrowing.
2. Building cubes.
3. Holdfasts/ peduncle.

Find the suitable substratum against each adaptation.

A village health worker was taking a session with women. She tells the women that one has to be very careful while using oral pills as method of birth control. Wrong usage can actually promote conception.
Analyse the statement and compare the merits and demerits of using oral pills and surgical methods of birth control.

Explain the steps involved in the production of genetically engineered insulin. Name the source from which insulin was extracted earlier. Why is this insulin no more in use by diabetic people?

Explain the pyramid of energy in ecosystem. ###What is meant by ecological pyramid? Describe an ideal pyramid of energy with diagram.