Evolution — BIOLOGY STD 12 Science — Question

Draw a picture of viral replication. Write the full name of AIDS pathogen. How does hybridization occur? Explain the symptoms of AIDS in human body.

Pistil of a flower does not accept pollen from any plant other than from its own kind. How does it happen? Explain.

What is Mutation? Describe the main points of mutation theory?

A child has blood group O. If the father has blood group A and mother blood group B, work out the genotypes of the parents and the possible genotypes of the other offsprings.

What does an Ecological Pyramid indicate? Explain the three different types of Upright Pyramids in nature with the help of an example of each.

In which categories have been classified the contraceptive methods. Describe any three methods in detail.

Looking at the deteriorating air quality because of air pollution in many cities of the country, the citizens are very much worried and concerned about their health. The doctors have declared health emergency in the cities where the air quality is very severely poor.

1. Mention any two major causes of air pollution.
2. Write any two harmful effects of air pollution to plants and humans.
3. As a captain of your school Eco-club, suggest any two programmes you would plan to organise in the school so as to bring awareness among the students on how to check air pollution in and around the school.

Describe the components of an ecosystem.

Explain the law of dominance by Punnet Square method.

1. List the three different allelic forms of gene ‘I’ in humans. Explain the different phenotypic expressions, controlled by these three forms.
2. A woman with blood group'A'marries a man with blood group 'O'. Discuss the possibilities of the inheritance of the blood groups in the following, starting with 'yes' or 'no' for each:

1. They produce children with blood group ‘A’ only.
2. They produce children, some with 'O' blood group and some with 'A' blood group.