Diffusion is the over all movement of molecules from one region where it is in high concentration to another another region where it is in lower concentration.
This movement continues until the concentration of both regions are equal. Smaller non polar molecules are able to diffuse through the lipid bilayer of the membrane .
Movement through the membrane is dependent on the concentration gradient, that is the difference in concentration between the two areas.
Answer:
It would be b. 1 TT: 2Tt: 1 tt. Because crossing two heterozygous parents means the genotypes for them are Tt and Tt. Which means that there is only one way to get TT or tt and 2 ways to get Tt
