The number of pair$(s)$ of sex chromosomes in the zygote of humans is

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:

New species may be formed,if $......\,.$
$(i)$ $DNA$ undergoes significant changes in germ cells.
$(ii)$ there is no change in the genetic material.
$(iii)$ mating does not take place.

How can we say that a change in genes can bring about a change in $DNA$?

Give the pair of contrasting traits for the following characters in a pea plant and mention which is dominant and which is recessive:
$(i)$ Yellow seed
$(ii)$ Round seed

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