Earth's greenhouse effect problem is important because A) it ...

[EAugust]

Earth's greenhouse effect problem is important because
 
  A) it is a result of our use of nuclear energy, one of our prime sources of energy.
  B) it could cause increased skin cancer.
  C) it might warm up our entire planet.
  D) we must breath CO2 in order to live.
  E) CO2 is a toxic pollutant.

Question 2

Astronauts, in satellites orbiting Earth, feel weightless. Are they really weightless?
 
  A) Yes, because the centrifugal force due to their circular motion balances the force of gravity.
  B) Yes, because they are not in Earth's gravitational field.
  C) Yes, because they are falling around Earth.
  D) No, because the gravitational force is pulling downward on them.
  E) No, because the centrifugal force is pulling outward on them.

[qytan]

Answer to Question 1

C

Answer to Question 2

D

[EAugust]

Excellent

[connor417]

Gracias!