9 1 point
"Stiff, protective outer layer of plant cells" describes which organelle?
A. cell wall
B. cytoplasm
C. cell membrane
D. nuclear membrane

A. Cell wall

Explanation:

The cell wall is only found in plants, and is what gives the plant it's structure. This is why it is "Stiff" and "Protective"

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what do the different brain waves do?

explanation:

brainwaves are produced by synchronised electrical pulses from masses of neurons communicating with each other. brainwaves are detected using sensors placed on the scalp. brainwave speed is measured in hertz (cycles per second) and they are divided into bands delineating slow, moderate, and fast waves.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.