Evolution — BIOLOGY STD 12 Science — Question

Seeds of different genetic strains are kept for long periods in seed banks. Explain the conservative strategy involved in this process.

Highlight any four areas where genetic modification of plants has been useful.

Suggest some important steps that you would recommend to be taken to improve the reproductive health standards in india.

What is gene therapy? Name the first clinical case where it was used.

Heat loss or heat gain depends upon the surface area of the organism's body. Explain with the help of a suitable example.

OR

Explain, why are small animals rarely found in the polar regions?

Write a short note on ovaries.

Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.p

A, B, D are three independently assorting genes with their recessive alleles a, b, d, respectively. A cross was made between individuals of Aa bb DD genotype with aa bb dd. Find out the type of genotypes of the offspring produced.

Give any two similarities between the behaviour of genes (Mendel's factors) during inheritance and of chromosomes during cell division.

The backbone of DNA strands contains atoms joined by covalent bonds, whereas the bases between the two strands are hydrogen bonded. Based upon your knowledge of bonds, what is the significance of the type of bonding existing in a DNA molecule?