Question

When a paramecium, a single-celled organism, is
living under stressful conditions, it sometimes
switches from asexual to sexual reproduction.
The main advantage when this switch occurs is
that the paramecium is most likely to
(1) produce fewer offspring
(2) increase variation among its offspring
(3) avoid having to find a mate
(4) produce clones of itself

Answer 1

The answer is (2) increase variation among its offspring. More variation means that the offspring may be able to mutate/get a characteristic that helps them survive against the stressful conditions.

Answer 2

2) increase variation among its offspring