Answer:
three types of stimuli—mechanical, thermal, and chemical; some endings respond primarily to one type of stimulation, whereas other endings can detect all types. Chemical substances produced by the body that excite pain receptors include bradykinin, serotonin, and histamine."
Explanation:
From edge
The function of the cell membrane is to protect the cell from any outer surroundings that could be harmful to it.
Answer:
Shape, Size, Height, Type of Food
Explanation:
The color is the variable and the type of hummingbird can't be controlled.
hot and dry
i need 20 things so this was just randomly added. hot and dry is the answer