This question is related to the formation of sill through volcanic activity. See the explanation below.
What is responsible for the coarseness of sills?
The reason for the variance in the coarseness of grains is the formation of igneous rocks happens deep in the earth and on this surface.
The texture of the sill is dependent on the rate at which it cools.
Coarse-grained sills are formed deep within the earth's crust while the other cool rapidly on the earth's surface.
Learn more about sills at:
https://brainly.com/question/2018985
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