Without crossing over:

A. cells could not complete meiosis.
B. meiosis could not produce haploid gametes.
C. only a small number of unique gametes could be produced by a single individual.
D. genetic recombination could not occur.

D. Genetic recombination would not occur.  

Explanation:

If this did not occur, all individuals would be identical to its parent unless a mutation occurred.

it would be c. xylem.

idk and i also need to know where are those bio brainy acts lol