Since the traits inherit independently there is appearance of new combinations of characters in F₂ progeny.

(a) Round yellow - RRYY,
      Round green - Rryy,
      Wrinkled yellow - rr YY and 
      Wrinkled green - rryy
(b) Occur in the ratio of 9 : 3 : 3 : 1 respectively.

RrYy (Round yellow).

Evolution is the sequence of gradual changes which take place in the primitive organisms over millions of years in which new species are produced.
(a)It is through the constant process of evolution taking place in the organisms since the origin of life that such an enormous variety of plants and animals have come to exist on this earth at present.
(b)There is an inbuilt tendency to variation during reproduction due to errors in DNA copying and as a result of sexual reproduction.
(c) Fossils are the remains of impressions of dead plants or animals which died millions of
years ago. They study of fossils helps us to know about the evolution of species. Fossils tell us how new species are developed from the old. Fossils provide evidence of evolution by revealing characteristics of past organisms and the changes that have occurred these organisms to give rise to present organisms. Therefore, fossils have an importance in deciding evolutionary relationship.

(a) Characters are controlled by genes.
(b) Each gene controls one character.
(c) There may be two or more forms of the gene.
(d) One form may be dominant over the other.
(e) Genes are present on chromosomes.
(f) All individuals will have two forms of the gene whether similar or dissimilar.
(g) The two forms separate at the time of gamete formation and brought together in the zygote.