Final answer:
The statement is true; atresia of all but the dominant follicle during the follicular phase is caused by the decreased secretion of FSH, influenced by negative feedback from elevated estrogen levels.
Step-by-step explanation:
The statement that atresia of all but the dominant follicle is in part a result of the diminished secretion of follicle-stimulating hormone (FSH) during the second week of the follicular phase is true. As the follicular phase progresses, typically in a 28-day menstrual cycle, there is negative feedback on FSH production due to increased levels of estrogen from developing tertiary follicles.
Eventually, this negative feedback leads to a reduction in FSH levels, causing atresia (degeneration) of most developing follicles. However, the dominant follicle survives the reduction in FSH, likely due to its size, the number of granulosa cells, and FSH receptors that these cells possess. This process ensures that typically only one follicle, the dominant follicle, will continue to grow and eventually ovulate an oocyte on around day 14 of the menstrual cycle.