Principles of I...

Who discovered that chromosome number is fixed for a species.

Identify the scientists from the hints given: (i) They used chromosome movement to explain Mendel's laws. (ii) They noted that behaviour of chromosomes was parallel to the behaviour of genes.

In our society women are blamed for producing a female child. Choose the correct answer for sex determination in humans due to

A Drosophila has XXXYY sex chromosomes. All the autosomal chromosomes are normal. The sexual phenotype will be.

Choose the correct statements with reference to mutation theory :
(a) Mutations occur from time to time in naturally breeding population.
(b) Mutations are continuous and accumulate over generations.
(c) Mutations are full fledged and there are no intermediate forms.
(d) Mutations are not subjected to natural selection.

In this human pedigree the filled symbols represent the affected individuals. Identify the type of this pedigree.

From the pedigree chart of a family, one can make an analysis that it is on.

In which female has a pair of XX chromosomes?

Chick Pea is being grown in area where bacterial blight is common. What measures (a - d) should be taken
(a) Spraying Bordeaux mixture
(b) Controlling insect or vector of pathogen
(c) Use disease free seeds
(d) Use seeds of disease resistant variety.

In pedigree method of hybridisation upto which generation the plants are tested and released for cultivation