Advantage of cleistogamy is

• higher genetic variability

• more vigorous offspring

• no dependence on pollinators

• vivipary

Monoecious plant of Chara shows occurrence of

• antheridiophore and archegoniophore on the same plant

• stamen and carpel on the same plant

• upper antheridium and lower oogonium on the same plant

• upper oogonium and lower antheridium on the same plant

Perisperm differs from endosperm in

• being a haploid tissue

• having no reserve food

• being a diploid tissue

• its formation by fusion of secondary nucleus with several sperms

Which of the, following statements is not true of two genes that show 50% recombination frequency?

• the genes may be on different chromosomes

• the genes are tightly linked

• the genes show independent assortment

• if the genes are present on the same chromosome, they undergo more than one cross overs in every meiosis

Variation in gene frequencies within populations can occur by chance rather than by natural selection. This is referred to as

• genetic flow

• genetic drift

• random mating

• genetic load

If two persons with 'AB' blood group marry and have sufficiently large number of children, these children could be classified as 'A' blood group : 'AB' blood group : 'B' blood group in 1 : 2 : 1 ratio. Modern technique of protein electrophoresis reveals presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of

• codominance

• incomplete dominance

• partial dominance

• complete dominance

57.

The process by which organisms with different evolutionary history evolve similar phenotypic adaptations in response to a common environmental challenge, is called

• natural selection

• convergent evolution

• non-random evolution

• adaptive radiation

The tendency of population to remain in genetic equilibrium may be disturbed by

• random mating

• lack of migration

• lack of mutations

• lack of random mating

Which of the following Bt crops is being grown in India by the farmers?

• Maize

• Cotton

• Brinjal

• Soyabean

A good producer of citric acid is

• Aspergillus

• Pseudomonas

• Clostridium

• Saccharomyces