Estrogen levels are highest on day number?

Looking at the chart... This follicle becomes the dominant follicle and is the one prepared to be released at ovulation. The dominant follicle produces estrogen as it grows (8), which peaks just before ovulation happens (7). For most people, the follicular phase lasts 10-22 days, but this can vary from cycle-to-cycle (4).

Explanation:

Estrogen levels rise and fall twice during the menstrual cycle. Estrogen levels rise during the mid-follicular phase and then drop precipitously after ovulation. This is followed by a secondary rise in estrogen levels during the mid-luteal phase with a decrease at the end of the menstrual cycle.

which ever one is showing doing the same exercise in time intervals such as 30 seconds or a minute several times.