Why do all the gametes formed in human females have an X chromosome?

Mention three important features of fossils which help in the study of evolution.

A zygote which has an X-chromosome inherited from the father will develop into a

All the human races like Africans, Asians, Europeans, Americans and others might have evolved from a common ancestor. Provide a few evidences in support of this view.

What are the combinations of character in the $F_2$ progeny? What are their ratios?

If the fossil of an organism is found in the deeper layers of earth, then we can predict that

From the list given below, select the character which can be acquired but not inherited

Which of the following statements is not true with respect to variation?

Give the basic features of the mechanism of inheritance.

Some dinosaurs had feathers although they could not fly but birds have feathers that help them to fly. In the context of evolution this means that

In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosome is/are
(i) large chromosome
(ii) small chromosome
(iii) Y-chromosome
(iv) X-chromosome

In the following crosses write the characteristics of the progeny

Give the pair of contrasting traits of the following characters in pea plant and mention which is dominant and recessive (ii) round seed

Study the following cross and showing self pollination in $F_1$, fill in the blank and answer the question that follows.

 

Two pea plants one with round green seeds ($RRyy$) and another with wrinkled yellow ($rrYY$) seeds produce $F_1$ progeny that have round, yellow ($RrYy$) seeds. When $F_1$ plants are selfed, the $F_2$ progeny will have new combination of characters. Choose the new combination from the following
(i) Round, yellow
(ii) Round, green
(iii) Wrinkled, yellow
(iv) Wrinkled, green

The maleness of a child is determined by

Which of the following statement is incorrect?

How is the sex of a newborn determined in humans?

Give the pair of contrasting traits of the following characters in pea plant and mention which is dominant and recessive (i) yellow seed

New species may be formed if
(i) DNA undergoes significant changes in germ cells
(ii) chromosome number changes in the gamete
(iii) there is no change in the genetic material
(iv) mating does not take place