Evolution — BIOLOGY STD 12 Science — Question

What are introns and exons? What process removes the unwanted RNA region and joins those that code for amino acids?

Mention the product and its use produced by each of the microbes listed below
(i) Steptococcus
(ii) Lactobacillus
(iii) Saccharomyces cerevisiae

Out of many papaya plants growing in your garden, only a few bear fruits Give reason.

A student on a school trip started sneezing and wheezing soon after reaching the hill station for no explained reasons. But, on return to the plains, the symptoms disappeared. What is such a response called? How does the body produce it?

How does an amoeba respond to unfavourable conditions, and on arrival of favourable conditions?

Banana is a parthenocarpic fruit whereas oranges show polyembryony. How are they different from each other with respect to seeds?

(i) Write the complete name of IUDs.
(ii) IUDs secreting the hormone are said to be best contraceptive to keep space between children. Why?

What do you understand by Red Data book? Explain briefly.

Differentiate between benign and malignant tumours.

Name the tissue which lines the inner surfaces of fallopian tube.