Answer:
The central processing unit (CPU)
Explanation:
Within a paragraph, different classes of sentences can be identified according to their hierarchy or their function, according to the context Reese should insert this idea at the beginning of his first paragraph.
<h3>What is a paragraph? </h3>
It is the fragment of a text and is made up of a set of main and secondary clauses, the latter known as subordinate clauses.
The main sentence is the one that marks the meaning of the paragraph and on which other sentences, qualified as secondary, depend.
The example is about the circulatory system that has the main idea, which is a complex internal transport mechanism of living beings possesses to move blood rich with nutrients and oxygen to all the different parts of the body.
Therefore, we can conclude that within a paragraph, different classes of sentences can be identified according to their hierarchy or their function, according to the context Reese should insert this idea at the beginning of his first paragraph.
Learn more about circulatory system here: brainly.com/question/10103458
