No, because mothers have a pair of X-chromosomes. All children will inherit an ‘X’ chromosome from their mother regardless of whether they are boys or girls.

(a) Fossils represent modes of preservation of ancient species.
(b) Fossils help in establishing evolutionary traits among organisms and their ancestors.
(c) Fossils help in establishing the time period in which organisms lived. 

Human females have two X chromosomes called sex chromosomes. During meiosis at the time of gamete formation, one X chromosome enters each gamete. Hence all the gametes possess an X chromosome.

The sex of an infant is determined by the type of sex chromosome contributed by the male gamete. Since the ratio of male gametes containing X chromosome and those containing Y chromosome is 50: 50, the statistical probability of male or a female infant is also 50: 50.

A small population of a species faces a greater threat of extinction than a larger population. Following are some genetic explanation for this:
(a) Inbreeding: A small population promotes inbreeding. This results in least number of variations being incorporated in subsequent generations.
(b) Genetic drift: A small population is more exposed to sudden changes in the environment. The genetic drift because of sudden changes has the potential to wipe off the entire population. 
(c) Inbreeding depression is another major problem of small population. This results in negative population growth which is further detrimental to the survival of the species. 

Structures which have a common basic structure but perform different functions are called homologous structures. e.g. fore limbs of reptiles, amphibians and mammals. Yes, they have common ancestor but variously modified to carry out different activities.

Though animals have a vast diversity in structures they probably do not have a common ancestry, because common ancestry may greatly limit the extent of diversity. As many of these diverse animals are inhabiting the same habitat, their evolution by geographical isolation and speciation is also not likely. Thus, a common ancestry for all the animals is not the likely theory.

(a) yellow — dominant
green — recessive
(b) round — dominant
wrinkled — recessive