(Q).
Q: Carbon released by burning fossil fuels contributes to what effect in the atmosphere? Choices: - shielding effect - smog effect - cloud effect - greenhouse effect A:
(A).
greenhouse effect

(Q).
Q: What kind of energy positions do electrons occupy during ground state? Choices: - closest energy positions - relative energy positions - highest energy positions - lowest energy positions A:
(A).
lowest energy positions

(Q).
Q: Genetic variation helps ensure that some organisms will survive if what happens? Choices: - they get eaten - there's an earthquake - they die - their environment changes A:
(A).
their environment changes