Brown spotting of the teeth in humans is caused by a dominant x-linked gene. if a man with normal teeth marries a woman with brown teeth who had a father with normal teeth, then of their daughters will have brown teeth. ave%20two%20barr%20bodies.
a 100%
b 50%
c 25%

25%

Explanation:

The female with brown teeth had a father with normal teeth. Since normal teeth is a recessive trait, the father would have been homozygous recessive for the trait and would have transmitted one recessive allele to the female. Therefore, the female is heterozygous dominant for brown teeth.

Let's assume that the allele for brown teeth is X^B while the one for normal teeth is X^b. The genotype of heterozygous dominant female would be X^BX^b and that of the male with normal teeth would be X^bY.

A cross between X^BX^b and X^bY gives progeny in following phenotype ratio= 1/4 daughter with brown teeth: 1/4 daughter with normal teeth: 1/4 son with brown teeth: 1/4 son with normal teeth. Therefore, the probability of having a daughter with brown teeth is = 25%

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.