Question

multiple choice
it acts on genotypes rather than phenotypes
it assures the survival of every fit individual.
on average, it favors the survival of individuals that have adaptive characteristics.
it always selects for more complex forms.
all of the choices are correct.

Explanation:

Natural selection acts on phenotypes (observable traits) since they are what interact with the environment, not genotypes directly. It does not guarantee the survival of every fit individual due to chance - events and limited resources. It favors the survival of individuals with adaptive characteristics on average as they are more likely to reproduce and pass on their genes. It does not always select for more complex forms; simple forms can be highly adaptive in certain environments.

Answer:

On average, it favors the survival of individuals that have adaptive characteristics.