Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Biology

Distinguish between the roles of flocs and anaerobic sludge digesters in sewage treatments.

How did Darwin explain adaptive radiation ? Give another example exhibiting adaptive radiation.

How are productivity, gross productivity, net primary productivity and secondary productivity interrelated ?

Explain adaptive radiation with the help of a suitable example.

How have transgenic animals proved to be beneficial in production of biological products?

How have transgenic animals proved to be beneficial in chemical safety testing?

Why are analogous structures a result of convergent evolution?

Cite an example where more than one adaptive radiations have occurred in an isolated geographical area. Name the type of evolution your example depicts and state why it is so named.

Explain the process of sewage water treatment before it can be discharged into natural water bodies.

Differentiate between the following:

Dominance and Recessive

Differentiate between the following:

Homozygous and Heterozygous

Differentiate between the following:

Monohybrid and Dihybrid

When a cross is made between tall plant with yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be:

1. Tall and green.
2. Dwarf and green.

A child has blood group O. If the father has blood group A and the mother has blood group B, work out the genotypes of the parents and the possible genotypes of the other offspring.

Describe one example of adaptive radiation.

What is sewage?

What is the key difference between primary and secondary sewage treatment?

Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each, assuming the river water is relatively clean?

Can you think and answer how a reporter enzyme can be used to monitor the transformation of host cells by foreign DNA in addition to a selectable marker?

Describe briefly the following:

Origin of replication