Answer:
1 = A
2 = B
3 = B
Explanation:
1) Black holes occur when really big stars collapse on themselves. And, in order to get big, the star has to be an old one.
2) A black hole is something huge that swallows up everything, while a protostar is just the very beginning of a star.
3) Scientist can't truly know for sure, but they can infer about them due to the effects of the surrounding areas.
Answer:
The human population would eventually grow too large to be sufficiently supported by the food available.
Explanation:
He found that food production did not increase at an exponential rate but instead increased more slowly.
An organism
because ALL organisms are made up of one or more cells! i hope this helped
Permian-Triassic extinction
The essential components of the human cardiovascular system are the heart, blood and blood vessels. It includes the pulmonary circulation, a "loop" through the lungs where blood is oxygenated; and the systemic circulation, a "loop" through the rest of the body to provide oxygenated blood.
Hope this helps!