Sheryl is observing ovarian slides taken from a female ape. All the cells show crossover chromosomes. What is this stage? ОА
meiotic prophasel
ОВ.
meiotic prophase II
Ос.
meiotic metaphase

meiotic prophasel

Explanation:

Crossing-over is a unique phenomenon that only occurs during meiotic division or gamete formation. It is the process whereby non-sister chromatids of homologous chromosomes exchange a portion of the their chromosome.

Crossing-over occurs specifically in the Prophase 1 stage of meiosis, where homologous chromosomes lie side by side to form a TETRAD structure and exchange their chromosomal segment. Crossing-over aims at promoting genetic diversity among sexually-reproducing organisms.

Therefore, an ovarian slide observed to show crossing-over occurs at the Prophase I stage of meiosis 1.

the bedroo..

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."