What are the 2 main ideas behind natural selection? (will give brainlist!)

In dna, only the_ varies from one nucleotide to another. base phosphate sugar amino acid

For this question look at the hydropic diagram water that is heated by the sun evaporates. select the number that represents it.

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?