<span>maintaining a stable internal environment</span>
Answer:
<u><em>Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs. </em></u>
<u><em>Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains.</em></u>
Explanation:
Aristotle based his classification system off of observations of animals, and used physical characteristics to divide animals into two groups
Answer:
any of numerous complex proteins that are produced by living cells and catalyze specific biochemical reactions at body temperatures
