Answer the following question given this paragraph: 

Figure 43.17 Rising and falling hormone levels result in progression of the ovarian and menstrual cycles. (credit: modification of work by Mikael Häggström).


Q: Rising and falling levels of what will result in progression of the ovarian and menstrual cycles?

 Choices:

- red blood cells

- oxygen

- blood pressure

- hormones

A:
hormones
