Asubstance that moves across a cell membrane
without using the cell's energy tends to move

Passive transport

Explanation:

A substance that moves across a cell membrane without using the cells energy tends to move from an area of high concentration to an area of low concentration. This is known as Passive transport.

the genotypes would be 50% bb and 50% bb

the phenotypes would be 50% brown and 50% white. hope this : )