Control and Co-ordination — BIOLOGY STD 12 Science — Question

Which three options could be thought for increasing food production?

Study the age pyramids ‘A’, ‘B’ and ‘C’ of the human population given below and answer the questions that follow:

1. Identify pyramids ‘B’ and ‘C’.
2. Write the basis on which the above pyramids are plotted.

Scutellum is the single cotyledon found in the monocot embryo only. Explain.

Give scientific : Mr. Sharma suffered from a stroke and the right side of his body was paralysed. However his response was normal for knee jerk reflex with either leg. Explain how and why?

Ankit attended a blood donation camp to donate blood and came to know that he was HIV positive. He lost interest in studies knowing that. He remained absent from school for a long time. The biology teacher visited his house and talked to him. Ankit started coming to school again and showed interest in studies.

1. A person detected to be HIV positive should be isolated by the society. Do you agree? Why/ why not?
2. Write the processes through which, AIDS does not spread.
3. Who are at higher risk of encountering AIDS?
4. What sense of responsibility did the biology teacher exhibit?

Give reasons, why?

1. Cow dung is preferred for biogas production.
2. Saccharomyces cerevisiae is commonly known as baker's yeast.

With the help of diagram show arithmetic growth and geometric growth.

Differentiate between an annual and a biennial plant. Provide one example of each.

What do you mean by fragmented habitat? Give one example.