Final answer:
In a state of low energy availability, ovarian follicle development, production of estradiol, ovulation, and endometrial thickening will all decrease.
Step-by-step explanation:
When there is low energy available, various physiological changes can occur in the female reproductive system. Ovarian follicles require energy to develop properly, and in a low energy state, their growth and development can be inhibited, leading to a decrease in the number of follicles. As ovarian follicle are responsible for estradiol (a form of estrogen) production, a decrease in follicle development would result in a decrease in estradiol levels. Ovulation is dependent on a complex interplay of hormones, including estradiol, which helps trigger the LH surge essential for the release of an egg. Reduction in estradiol would therefore likely lead to a decrease in or absence of ovulation .
Furthermore, estradiol has a critical role in preparing the endometrium for potential implantation of an embryo. Low estradiol levels mean the endometrium may not proliferate as it should, hence leading to a decrease in the thickening of the endometrial lining. Hence, the correct answer to the question is that all of these functions—development of ovarian follicles, production of estradiol, ovulation, and endometrial thickening—will decrease when there is low energy available.