An animal cell that is placed in a hypotonic solution will rapidly gain water, because osmosis would cause the water to move to an area with more solutes. In this case, that is the inside of the cell. A cell in a hypotonic solution may gain enough water to lyse, or rupture, the cell membrane, which destroys the cell.
So: both parents' genotypes (concerning baldness gene) are the same: Bb. Possible genotypes of an offspring: BB, Bb, Bb, bb . bb means non-bald girl or boy. Bb means bald boy or non-bald girl. BB means bald boy or girl. there is 25% chance of conceiving a child with a genotype BB. But there is also 50% chance of conceiving a girl. So the answer is: 25% x 50% = 12,5%
C. The Bering Land Bridge once connected what would be Russia and North America but the the movement of these continents separated the land bridge