A red animal (AA dominant) mates with a yellow animal (aa recessive). What would be the genotype and phenotype of a heterozygous offspring? (Assuming complete dominance)
a. phenotype (yellow): genotype Aa
b. phenotype (red); genotype AA
c. phenotype (yellow); genotype aa
d. phenotype (red): genotype Aa

d.phenotype red: genotype Aa

Explanation:

a red animal that is a Donna Mae a would still have dominance over the yellow animal it recessive so if you put it in the chart form AA would be on top and the lowercase a a would be on the left side so it would be phenotype red genotype capital a lowercase a .

enzyme speed up the reactions

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!