Why does sexual reproduction increase the genetic variation in a species?
a. a fertilized egg has a mixture of alleles from the two parents.
b, sexual reproduction doubles the chromosome number
c. the gametes in sexual reproduction are exact clones of the parents.
d. sexual reproduction produces organisms with no dna.

A. A fertilized egg has a mixture of alleles from the two parents.

Sexual reproduction is a method of production of new organism by the fusion of gametes formed by two distinct parents. A single sperm fuses with the egg. The genes of the two parents combines in this process. During the gamete formation a pair of allele gets segregated from each parent and a single copy of allele is obtained from each parent. Therefore, a fertilized egg contains a mixture of alleles obtained from both parents this is the result of genetic variations in a species. The offspring is not exactly identical to either of the parents but exhibit genetic variations.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.