Question Bank [2022] — BIOLOGY STD 12 Science — Question

Explain how loss of species diversity can harm ecosystem?

Give reasons : Water hyacinth is called ‘Terror of Bengal’.

Pihu told her sister Pari that even after five years of marriage she is not able to bear a child and have to hear sarcastic remarks of her in-laws that make her depressed. Pari told Pihu that she and her husband should get examined by a doctor. After examination, doctor found no abnormalities in Pihu and her husband except low sperm count and some defects in the erection of penis of her husband.

1. What are the possible causes of low sperm counts?
2. What is the use of erection of penis?
3. What are the possible treatments?
4. Mention the values shown by Pari.

Write the differences between wind-pollinated and insect-pollinated flowers. Give an example of each type.

Blood plasma.

Highlight the differences and a similarity between the following population interactions: competition, predation and commensalism.

How cancer is detected and diagnosed?

List any three important characteristics of a population and explain.

1. Define life span.
2. Mention the life span of:

1. Crocodile.
2. Crow.
3. Parrot and
4. Butterfly.