Read the excerpt from silent spring.
in the gutters under the eaves and between the shingles of the roofs, a white granular powder still showed a few patches; some weeks before it had fallen like snow upon the roofs and the lawns, the fields and streams.
which best explains how the phrase "white granular powder" supports the author’s purpose of calling attention to the environment?

Your question is incomplete because you have not provided the options. These are as follows:

the powder is an unnatural substance.

the powder has a texture like sugar.

the powder looks like freshly fallen snow.

the powder is used in house construction.

The powder is an unnatural substance.

Explanation:

In in the excerpt from "Silent Spring," the author Rachel Carson makes reference to the effect that chemical poisons has caused in the atmosphere. In fact, she depicts a spring scene in which fine white particles of poison can still be seen on plants and roofs, and mentions that it had fallen heavily some weeks before.

A) The powder is an unnatural substance.

Explanation:

edge 2020

taking into account that a theme is the central topic a text treats and can be developed through a story, play, poem etc. the following are themes that can be further developed:  

my best friend jeffrey has many unusual interests. (the story could be about each of the unususal interests)

once a man gives his soul over to evil, he can never go back. (this could be a saying or a proverb)

the three sheepdogs lay around the yard all day. (it could be developed detailing how each of these sheepdogs lay around)

a priest's collar has an unusual effect upon people. (it could be developed detailing the different effect upon people)

innocence is a powerful force in a world full of corruption. (it could be developed detailing how is a world full of corruption)

king lear is a play shakespeare wrote later. (it is just a sentence and doesnt give any idea or topic to be discussed in details.

evil often wears the disguise of innocence. (this could be a saying or a proverb)

ccd puts the honeybee populations and crop health at risk.

the above detail from paragraph 2 supports the inference about honeybee.