A primary oocyte residing in a primordial follicle becomes a secondary oocyte "in the vesicular follicle".
Crossing over, or recombination, is the exchange of chromosome segments between nonsister chromatids in meiosis. Crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity.
Hope it helps
I can't draw very well. but, essentially the shape of DNA is a double helix and A pairs with T and T pairs with A. C pairs with G and G pairs with C. No matter what in DNA. What one side has the other side has. The other will always have the match to it on the other side
A= adenine
T=thymine
C=Cytosine
G=guanine