Human Reproduction — BIOLOGY STD 12 Science — Question

List the four important changes, taking place during biotic succession.

'in-situ' conservation can help endangered/threatened species. Justify the statement.

Explain the role of the enzyme EcoRI in recombinant DNA technology.

Explain co-evolution with reference to parasites and their hosts. Mention any four special adaptive features evolved in parasites for their parasitic mode of life.

OR

Explain parasitism and co-evolution with the help of one example of each.

What could be the possible explanation for greater vulnerability of amphibians to extinction as compared to other animal groups?

A patient complains of suffering from constipation, stomach ache, stool with blood clots and excess mucous.
The physician diagnosed it as amoebiasis, after stool test.
a. Write the scientific name of the microbe identified in the stool sample.
b. How do you think, the patient must have contracted it?
c. Write your suggestions to the patient to avoid infection in future.

(a) Describe the role of selectable marker in r-DNA technology.
(b) Write the name of one such selectable marker considered useful for E. coli.
(c) Write one reason why it is considered an advantageous selectable marker

State in what ways Stanley Miller stimulated the conditions of-

1. Primitive atmosphere on earth.
2. Energy source at the time of origin of life.
3. Formation of organic molecules of life to prove the theory of chemical evolution.

List any four symptoms shown by Klinefelter’s syndrome sufferer. Explain the cause of this disease.