(a) Fig. 4.1 shows changes in the thickness of the uterus lining and in the concentration of progesterone in the blood during the menstrual cycle. thickness of uterus lining concentration of progesterone in the blood menstruation begins time/days [Figure 4.1]

1. (a)(i)Use Fig. 4.1 to state the time at which each of the following occurs: the uterus lining reaches maximum thickness the concentration of progesterone begins to increase.[2]
2. (a)(ii)Draw a ring around the day from Fig. 4.1 on which ovulation is most likely to occur. day 0 day 7 day 14 day 21 day 28[1]
3. (a)(iii)Explain how it can be concluded from Fig. 4.1 that the person did not become pregnant during the 28 days shown, even though ovulation occurred.[2]
4. (b)The menstrual cycle is controlled by hormones. Name two hormones, other than progesterone, that control the menstrual cycle. State one role of each hormone. name of hormone role in the menstrual cycle name of hormone role in the menstrual cycle[4]

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