Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Explain giving three reasons why tropics show, greatest level of species diversity.

What happens to an individual when a regular dose of drugs/ alcohol is abruptly discontinued? What characteristics manifest in the individual under such a situation?
OR
What is 'withdrawal syndrome'? List any two symptoms it is characterised by.

The following graph shows the species-area relationship. Answer the following questions as directed.

1. Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him.
2. Write the situations as discovered by the ecologists when the value of Z (slope of the line) lies between (a) 0.1 and 0.2 (b) 0.6 and 1.2. What does Z stand for?
3. When would the slope of the line 'B' become steeper?

An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?

What are the conditions in which medical termination of pregnancy is advised?

Differentiate between ‘ZZ’ and ‘XY’ type of sex-determination mechanisms.

Give the term for each of the following:

1. The condition in which both male and female reproductive organs are found on the same plant.
2. The condition in which both male and female parts are present on the different plants.
3. Animals that remain reproductively active throughout their reproductive phase.
4. Animals that remain reproductively active only during the favourable seasons in their reproductive phase.

“Bt toxin synthesized by some bacteria kills insects carrying protein, but not themselves.” Explain the statement with reasons.

How did a citizen group called Friends of Arcata Marsh, Arcata, California, USA, help to improve water quality of the marshland using Integrated Waste Water Treatment? Explain in four steps.

Name the source used to produce hepatitis-B vaccine using rDNA technology.