Question

Which of the following is true about natural selection?

A. Natural selection is the only cause of changes in a species.
B. Natural selection usually causes a species to change suddenly.
C. Natural selection does not cause a species to change.
D. Natural selection usually causes a species to change gradually.

Answer 1

B

Step-by-step explanation:

only the individuals with certain genetic markers and therefore abilities to survive a given threat, can reproduce. which has a changing effect for the species within only very few generations. which is on the timescale of evolution a sudden change.

but it depends on the nature of the threat.

if the threat itself develops slowly, then natural selection will also cause a slow change.

if the threat appears suddenly in full force, so will the change by natural selection.

immunization by vaccination turns the threat into slow mode, as it continues to being a threat by mutations.