Based on Lyon’s hypothesis, what will be the number of Barr bodies found in a human female suffering from Down’s syndrome

In which one of the following combinations (a-d) of the number of the chromosomes is the present day hexaploid wheat correctly represented?

Mongolism syndrome is caused by

Which of these is a dominant factor?

In a cross between white-flowered parents, $F_1$ progeny was uniformly purple-flowered. The $F_2$ progeny showed a phenotypic ratio $9 : 7$ between purple-flowered and white-flowered plants. The above result indicates that the flower colour is controlled by

Expected children of a blue-eyed $(recessive)$ woman and brown-eyed $(dominant)$ man who had a blue-eyed mother are likely to be