Human Reproduction — BIOLOGY STD 12 Science — Question

Ankit attended a blood donation camp to donate blood and came to know that he was HIV positive. He lost interest in studies knowing that. He remained absent from school for a long time. The biology teacher visited his house and talked to him. Ankit started coming to school again and showed interest in studies.

1. A person detected to be HIV positive should be isolated by the society. Do you agree? Why/ why not?
2. Write the processes through which, AIDS does not spread.
3. Who are at higher risk of encountering AIDS?
4. What sense of responsibility did the biology teacher exhibit?

What are the fundamental difference between In-situ and Ex-situ conservation.

Explain the efforts which must be put in to improve health, hygiene and milk yield of cattle in a dairy farm.

Explain the difference between commensalism and mutualism types of interactions, with the help of a suitable example of each.

What is apomixis and what is its importance?

In cattle, hornless (H) is dominant over horned (h) and black (B) is dominant over red (b). Consider that these two pairs of genes assort independently.

1. What proportion of the offspring from the cross, BbHh x bbhh, would be black and hornless?
2. From the cross Bbhh x Bbhh, how many will be:

1. Black and horned.
2. Red and horned.

In haploid organisms that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs. Give reasons for your answer.

Mention the name of the causal organism, symptoms and the mode of transmission of the disease Amoebiasis.

A factory drains its waste water into the nearby lake. It has caused algal bloom.
How was the algal bloom caused?

What do you understand by the term population explosion? What are the reasons for population explosion?