Organisms and Populations — BIOLOGY STD 12 Science — Question

Rohan and his friends emptied all the overhead tanks, which were not in use for last few months. Some people did not like this. Rohan and his friends explained and convinced them about the hygienic benefits of their act.

1. What was the objective behind their act?
2. Explain in brief the stages of life cycle of a malarial parasite in human body.
3. Which pathogen is responsible for malaria?
4. What values did Rahul and his friends promote?

Explain the development of a secondary oocyte (ovum) in human female from the embryonic stage upto its ovulation. Name the hormones involved in this process.

1. How does the study of fossils help to understand evolution?
2. How did SL Miller provide an experimental evidence in favour of Oparin and Haldane's hypothesis? Explain.

1. Trace the succession of plants on a dry bare rock.
2. How does phosphorus cycle differ from carbon cycle?

Using Punnett square demonstrate the law of independent assortment in a dihybrid cross involving two heterozygous parents.

1. State the cause and symptoms of colour-blindness in humans.
2. Statistical data has shown that 8% of the human males are colour-blind whereas only 0.4% of females are colour-blind. Explain giving reasons how is it so.

Answer the following questions:
Describe the stages of oogenesis in human females.

Trace the development of microspore mother cell in the anther to a mature pollen grain.

What is the Human Genome Project? Write the features of the Human Genome Project. Give a diagram representing the Human Genome Project.

State the laws of inheritance that can be derived from such a cross.