CBSE Class 12 Biology Questionbank

Double fertilisation in angiosperms produces:

Fertilisation in humans normally occurs in the:

Copper-T is an example of a:

A test cross that yields offspring in a 1:1 ratio of dominant to recessive phenotypes indicates the unknown parent is:

The Hershey-Chase experiment proved DNA is the genetic material by labelling proteins with $^{35}S$ and DNA with:

Assertion: Darwin's finches of the Galapagos Islands are an example of adaptive radiation.

Reason: Their beak sizes and shapes diversified to exploit different food sources on different islands.

A population has a birth rate of 20 per 1000 and a death rate of 8 per 1000 per year. Find its percentage growth rate per year.

The HIV virus that causes AIDS primarily attacks:

Curd is formed from milk by the action of:

The restriction enzyme EcoRI recognises and cuts the palindromic sequence:

Bt cotton is resistant to bollworms because the bacterium Bacillus thuringiensis produces a protein that:

A population growing logistically eventually levels off at the:

Applying the 10% law: if producers capture 10000 J of energy, how much energy (in J) reaches a third-level carnivore (fourth trophic level)?

Net primary productivity (NPP) equals gross primary productivity minus:

Protecting a forest as a national park is an example of:

In a population at Hardy-Weinberg equilibrium, the frequency of the recessive allele is q = 0.4. Find the frequency of heterozygotes (2pq).