Question

When part of a glacier melts and reveals solid rock, very few plants can live in the new environment. Some grasses can grow around the cracks in rocks. Because they are some of the first organisms to live in an area, they are known as pioneer species. How can these organisms change the environment to make it more suitable for other organisms?

A.
They increase the amount of sunlight.
B.
They make water more readily available.
C.
They provide competition for resources.
D.
They contribute to the formation of soil.

Answer 1

They contribute to the formation of soil.

Step-by-step explanation:

Grasses that live in rocky places can speed up the process of weathering rocks. The small pieces of rock formed by weathering are part of the soil. Additionally, dead lichen and grasses provide nutrients for the soil.

Therefore, these organisms can change the environment to make it more suitable for other organisms by contributing to the formation of soil.

Answer 2

D

This is an example of a pioneer species initiating primary succession.

Step-by-step explanation:

These pioneer species help break down the rock into soil. Most of the times they are lichens and moss that form a symbiotic relationship. In this case, you can realize the other choices do not make much sense.

A says that they will increase the amount of sunlight, but how is that even possible? A plant could not increase the amount of sunlight, that it totally independent of anything.

B says they make water more readily available. This also does not make that much sense as how would the plants be able to do this?

C says they provide competition. In that case, that would not make it more suitable for other organisms.