The Sun appears to move across the sky each day. What causes this?

The earth is turning.

Explanation:

when the earth turns it causes the sun to move from one part of the sky to the other. The earth revolves around the sun. So when it become night time for example, the sun is just on the other side of the earth.

i don't know, but does anyone wanna be friends? i'm doing my homework at 1: 49 in the morning : /

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.