Alicia is solving a math equation. she is using her cerebrum cerebellum medulla plexus

I believe it is C. Medulla 

I hope this helps you :)
Sorry if i was wrong

answer and explanation;

composition refers to both the types of minerals within a rock and the overall chemical makeup of the rock while texture refers to the size and arrangement of the minerals or grains that make up a rock. both composition and texture can be used to classify rocks, such as igneous rocks. texture describes how the rock became solid or crystallized from liquid, melted rock. composition of a rock describes the minerals that make up a particular rock.

You will hear a hissing sound because of the carbon dioxide escaping the can or bottle