Asubstance that moves across a cell membrane without using the cells energy tends to move

From their region of high concentration to their region of low concentration.

Explanation:

A substance that moves across a cell membrane without using the cells energy tends to move from  their region of high concentration to their region of low concentration. A good example of such a process would be Osmosis.

On the other hand if the substance moves across a cell membrane and requires the use of energy then it tends to move against a concentration gradient, as is the case with Active transport.

the answer is: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall.

there is no stairs in bungalow

explanation:

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