What is one part of a nucleotide that differs among the 4 different nucleotide

Round seeds and yellow seed color are dominant to wrinkled seeds and green seed color. which punnett square represents the correct way to set up the cross rryy  ´  rryy? 

What does the hardy-weinberg principle relate to? a. chances of survival of an organism b. frequency of alleles in a population c. natural selection in a species d. causes of evolution among organisms

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of