## Problem 323 — rank:204

**Title:** Evolution of menstruation

**Added binding assumptions (LaTeX):**

```latex
Interpret the contrast as a controlled feasible strategy comparison at fixed decidualization and resident context, not adjustment for an endogenous mediator in observational data. If the two strategies cannot exist separately under the allowed physiology, the isolated shedding effect is not an admissible estimand. Expected descendant contribution uses a stated demographic normalization. Evidence of current physiological effects is distinct from evidence of historical selection on shedding itself.
```

**Direct edits:** 0. **Fresh external checks:** None; supplied sources retained as provenance.