|1. what is:
a) an element?
b) compound?
c) mixture?

When it is summer at the south pole, a. the northern hemisphere is tilted toward the sun. b. the southern hemisphere is tilted away from the sun. c. the northern hemisphere is tilted away from the sun. d. both the southern and northern hemispheres are tilted toward the sun.

The diagram is represented of a part of a plant cell. identify the locations where proton concentration builds up during photosynthesis and cellular respiration

Describe the structure of a virus, and explain how this structure differs from that of a cell.