Climates near the equator are warmer than at the poles because
a. the sun's rays have greater energy at the equator
b. the sun's rays are more concentrated at the equator
c. ice at the poles absorbs the sun's rays
d. the equator is near a low-pressure belt

The correct answer is (b) The Sun's rays are more concentrated at the equator

The rays at the equator are more concentrated and as a result of this the equator is warmer than the pole. The hotness of the place depends on the angle by which the sun ray falls on it. When the sun ray falls on the equator then the angle made by the sun at equator is 90 degree. This means that the sun rays are concentrated. But at poles the angle by which the rays fall is relatively shallow and the rays gets separated over a large area.

This makes equator more warmer than pole.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.

more words for this could be abiotic and biotic

abiotic: living organisms within an ecosystem

biotic: non-living organisms within an ecosystem