Pollination is an example of
a possible source of new drugs
chemical diversity
an ecosystem service
crop pest control

The correct answer is C. An ecosystem service

Explanation:

In ecology, an ecosystem service refers to processes or elements that are part of the natural environment but besides this represent benefits for humans, this includes organisms and processes involved in the decomposition of waste and also pollination. Pollination is an example of an ecosystem service because, in pollination insects, birds and other organism or even wind transfer pollen which makes possible plants fertilization and this is essential for crops in agriculture, which means humans benefit for pollination and therefore this is an ecosystem service.