Menstrual cycle online exercise for - Free Printable

Explanation:
We need to match each phase of the menstrual cycle with the correct description, based on the days shown and what happens in each stage.

Let’s go step by step using standard knowledge of the menstrual cycle (28-day cycle is typical):

1. Day 1–5: This is the Period (menstruation) — the uterine lining sheds because no pregnancy occurred last cycle. In the diagram, the top-right uterus shows shedding (red dots = blood/lining coming out), labeled “1st day” to “3rd” or so → this matches Period (menstruation).

2. Day 5–14: After menstruation, the lining starts to rebuild — it *thickens* under estrogen from developing follicles. So around day 6–14, we see “Lining starts to thicken”. In the diagram, the bottom-right uterus (around day 10–14) shows a thin but growing red lining — that’s the proliferative phase. So the box pointing to ~day 10 should be Lining starts to thicken.

3. Around Day 14: Ovulation occurs — the egg is released from the ovary. In the diagram, the bottom uterus (around day 14–15) shows an egg being released (arrow from ovary), and the lining is thickening. So the box pointing to ~day 14–15 is Egg released (ovulation).

4. Day 15–28: After ovulation, the corpus luteum produces progesterone, and the lining becomes thick and secretory — ready for implantation.
- If the egg is fertilized → it implants into the thick lining → pregnancy begins.
- If not fertilized → the lining breaks down → period starts again on day 28/1.
So the left-side uterus (around day 21–25) shows a very thick red lining — that’s the secretory phase. The box pointing there (left side, ~day 22–25) should be: If egg is fertilised it settles into thick lining.
And the top-left uterus (around day 25–28) shows the lining breaking down (less red, some shedding), leading into the next period — so that box is: Egg dies if not fertilised (because without fertilization, the egg degenerates ~24h after ovulation, and the corpus luteum breaks down, causing progesterone drop and menstruation).

Now let’s assign the boxes in order (clockwise, starting top-left, then top-right, bottom-right, bottom, bottom-left):

- Top-left box (points to ~day 25–28): Egg dies if not fertilised
- Top-right box (points to day 1–3): Period (menstruation)
- Bottom-right box (points to ~day 8–10): Lining starts to thicken
- Bottom box (points to day 14): Egg released (ovulation)
- Bottom-left box (points to ~day 18–22): If egg is fertilised it settles into thick lining

Wait — let’s double-check the arrows:

From the diagram:
- Arrow from top-left box points to ~day 25 (just before new period) → that’s when unfertilized egg has died and lining is about to shed → Egg dies if not fertilised
- Arrow from top-right box points to day 1–2 → Period (menstruation)
- Arrow from bottom-right box points to ~day 9–10 → early proliferative phase → Lining starts to thicken
- Arrow from bottom box points to day 14 → Egg released (ovulation)
- Arrow from bottom-left box points to ~day 17–20 → post-ovulation, lining is thick and ready → this is when *if fertilized*, implantation can happen → If egg is fertilised it settles into thick lining

Yes — that fits.

So final matching:
- Top-left box → Egg dies if not fertilised
- Top-right box → Period (menstruation)
- Bottom-right box → Lining starts to thicken
- Bottom box → Egg released (ovulation)
- Bottom-left box → If egg is fertilised it settles into thick lining

Final Answer:
Top-left: Egg dies if not fertilised
Top-right: Period (menstruation)
Bottom-right: Lining starts to thicken
Bottom: Egg released (ovulation)
Bottom-left: If egg is fertilised it settles into thick lining