Answer:
a,b,c,d
Explanation:
Variation (changes in genetic composition of an organism due to mutation),in fitness makes an organism to undergo natural selection or sexual selection. This is because such organisms are able to compete and acquire effectively the needed traits(gene) from parents, natural resources in the environments,to be fitted to reproduce successfully(higher gene pool) and therefore well populated to compete with other organisms in the same environment. Therefore they can withstand selective pressures, and naturally selected than others.
Variation in genotype of an organisms brings about effective gene flow which the organisms need to possess to adapt to changes in the selective pressures, and therefore to able to compete for natural resources than others, This makes these organisms to be well fitted to adapt to the environment and therefore naturally selected.
Variation in the environment, refers to changes in the selective pressure of the environment where the organisms are located. it is only organisms that are well fitted, of higher reproductive success,(gene pool)and and higher competition to survive because of acquired traits will be able to be naturally selected compare to others.
Variation of different phenotype caused by different genotype makes some organisms to be positively or negatively susceptible to certain environmental pressures than others. If this is negative; it reduces their reproductive success, their population, and therefore competition for survival , thus their chances to be naturally selected compare to organism with positive different phenotypic qualities for survival is low. E.g a white rabbit will be well spotted by a predator, compare to brown or agouti because of the different phenotype from different genotype
Note; Natural selective is not a random process. rather it is natural process that occur due to changes in the environmental pressure. Only variation can be random.
