Answer:
R group is the part of an amino acid and that is only one that varies and is what defines its properties
Answer:
D
Explanation:
In multicellular organisms, the body is a system of multiple, interacting subsystems. Subsystems are groups of cells that work together to form tissues. Interactions are limited to the circulatory, excretory, digestive, respiratory, muscular, and nervous systems.
<span>sperm, blood, hair with attached tissue</span>
