How could crossing over affect the distribution of the four alleles: A, a, B, and b?

A. Crossing over would always keep A and B together on the same chromosome, and keep a and b together on the same chromosome.
B. Crossing over would always put A and B on different chromosomes, and always put a and b on different chromosomes.
C. Crossing over would sometimes, but not always, exchange the positions of A and a, and of B and b, on homologous chromosomes.
D. Crossing over would sometimes, but not always, delete one or more of the four alleles from both homologous chromosomes.

The blue particles in this image are able to cross the cell membrane through simple diffusion. how will they be transported? outside the cell inside the cell o a. the substances will move directly across the membrane from outside the cell to inside the cell. b. the substances will move through channels in the membrane proteins from outside the cell to inside the cell. o c. the substances will move through channels in the membrane proteins from inside the cell to outside the cell. o d. the substances will move directly across the membrane from inside the cell to outside the cell.