Natural selection increases tuskless elephants via poaching pressure

Steps:

• Poaching kills tusked elephants more, increasing tuskless survival (statement 1).
• Tuskless trait is heritable, so survivors pass it to offspring (statement 2).
• Higher female tusklessness (10%) vs. males (5%) suggests X-linked inheritance, amplifying spread in females (statement 3).
• Combined, these explain rise from 10% overall to sex-biased prevalence.

Why A is correct:

• All three statements describe directional selection, heritability, and sex-linked transmission per evolutionary biology principles.

Why the others are wrong:

• B omits sex-linkage, failing to explain male-female difference.
• C ignores heritability and sex-linkage, missing genetic propagation.
• D excludes poaching survival advantage, the primary selective force.

Final answer: A