Answer:
because there was no doubt that flys and maggots were around dead meat but there was no independent variable or a control group
Explanation:
good luckkk
Channel proteins, also known as transport proteins, allow the passage of molecules in and out of the plasma membrane.
Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. ... Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and sensing.
Source:
https://en.m.wikipedia.org/wiki/Epithelium