During the process of fertilization, which step happens first?
a. the sperm s nucleus enters the egg cell.
b. enzymes break down the protective layer of the egg cell membrane.
c. a sperm attaches to a binding site on the egg cell membrane.
d. the cell membrane of the egg cell changes

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs