Human Reproduction — BIOLOGY STD 12 Science — Question

Describe the roles of pituitary and ovarian hormones during the menstrual cycle in a human female.

Explain the post pollination events up to double fertilisation, that occur in an angiosperm.

What is population explosion? Discuss the various reason of population explosion.

Who gave theory of use and disuse of organs? Discuss in detail the inheritance acquired character?

Answer the following questions:
Differentiate between gametogenesis in human males and females on the basis of:

1. Time of initiation of the process.
2. Products formed at the end of the process.

During the biology class on theories of evolution, the teacher was telling about Lamarckism. Katy was confused after listening to it and went to her teacher to clear her doubts. She asked if characters can be passed to generations, then why she does not have the tatoo that her mother has on her arm. The teacher smiled and told Katy that this is the reason why Lamarck's theory was rejected. The teacher explained her the other theories as well.

1. Name the book in which Lamarckism was explained.
2. What are the three factors of this theory?
3. What are the other theories of evolution?
4. What are the values shown by teacher?

Malarial parasite ‘Plasmodium’ completes its life cycle in two hosts. Draw its complete life cycle and explain various stages it follows throughout its life.

Use this key for Questions A-D Key:

1. thymus gland.
2. spleen.
3. lymph node.
4. red bone marrow.

1. Causes differentiation of T-cells.
2. Purifies lymph.
3. Contains red pulp and white pulp.
4. Formation of granular and a granular leukocytes.

In your locality, if a person is addicted to alcohol, what kind of behavioural changes do you observe in that person? Suggest measures to over come the problem.

Answer the following questions:
Seeds offer several advantages to angiosperms. Describe any three such advantages.