<u>Answer:</u>
Receptors
<u>Explanation: </u>
Receptors are specific for the particular parameter . They work to detect change and convert the change into signals that serves as a afferent input to the control center.
Negative feedback requires a receptors,control center, and a afferent. Generally a receptor monitors internal conditions. Receptors sense changes in function and initiate the body's homeostatic response.
Answer:
They speed up chemical reactions. Without them you wouldn't be alive. They break down macromolecules, and also lower the amount of energy needed for a chemical reaction to happen.
Please provide an image. But just for reference, a plant cell's main organelles are the cell wall, cell membrane, large water vacuole, nucleus, mitochondria, cloroplast, lysosme, golgi body, and some other organelles that may also be found in animal cells.