Air is made up of gas particles. These particles exert pressure on every object they collide against. This pressure is known as air pressure. Which of the following statements about air pressure is true?

A.
Air pressure increases as altitude increases.
B.
The atmosphere's air pressure does not vary.
C.
Air pressure decreases as altitude increases.
D.
Warm air tends to have a higher air pressure than cold air.

Hurry which of these is true about index fossils? a) are very scarcely found b) used as guides in relative dating c) found in the youngest layer of the rock d) used as reference points in absolute dating

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

Which of the following statements most accurately describes convergent evolution? the process in which two similar species evolve separately from each other and share similar characteristics the process in which a single species evolves into two or more new species the process in which two entirely different species evolve in response to each other the process in which two different species evolve separately from each other but still share similar characteristics