Model Paper 2 — BIOLOGY STD 12 Science — Question

With an example explain lattitude gradient, as a pattern of biodiversity.

Mention the different ways in which people are made aware of the significance of reproductive health and a reproductively healthy society.

Name the three layers of uterine wall.

Name two acid producing bacteria.

How has the use of Agrobacterium as vectors helped in controlling Meloidegyne incognitia infestation in tobacco plants? Explain in correct sequence.

A colour blind child is born to a normal couple. Work out a cross to show how it is possible. Mention the sex of this child.

During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again resume the original number (2n) in the offspring, what are the processes through which these events take place?

Prior a sports event blood and urine samples of sportspersons are collected for drug tests.

1. Why is there a need to conduct such tests?
2. Name the drugs the authorities usually look for.
3. Write the generic names of two plants from which these drugs are obtained.

Explain why Bt cotton flowers undergo pollination by butterflies and bees inspite of being insect pest resistant?