Question

the last ice age ended about 10,000 years ago. the glaciers retreated, leaving behind bare gravel, rocks, and sand. huge chunks of ice were also left where the glaciers had been for many thousands of years. these chunks of ice melted, creating small lakes and ponds. what are the first organisms that are most likely to have begun growing on the bare rock?
a. small shrubs such as dwarf willow
b. wildflowers such as fireweed
c. tall trees such as aspens and pines
d. pioneer species such as lichens

Explanation:

Pioneer species like lichens are the first to colonize bare rock in primary succession. They can break down rock and start soil - building, making it possible for other plants to grow later. Small shrubs, wildflowers, and tall trees require more developed soil conditions and cannot be the first on bare rock.

Answer:

D. pioneer species such as lichens