Reproduction in Lower and Higher Animals — BIOLOGY STD 12 Science — Question

Krishna was going to school and on the way he saw a major bus accident. His heartbeat increased and hands and feet become cold. Name the part of the nervous system that had a role to play in this reaction.

You have studied the story of Pepper moths in England. Had the industries been removed, what impact could it have on the moth population? Discuss.

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.

Dryopithecus.

Enlist advantages and disadvantages of cross pollination. Add a note on pollination mechanism in salvia.

1. Name the nuclei that fuse to form PEN.
2. What is the ploidy of PEN?
3. Explain the development of endosperm from PEN?

Explain the components of a transcription unit with the help of a diagram?

Species diversity decreases as we move away from the equator towards the poles. What could be the possible reasons?

What is organic farming? Discuss the benefits of organic farming as a viable practise in the context of developing nations like India.

Explain the different stages of oogenesis in humans starting from foetal life till its completion. When and where in the body is oogenesis completed?