31. Which of the following is not a natural greenhouse gas?
a) Methane
b) Nitrous oxide
c) Carbon dioxide
d) Oxygen
32. What is the term used to describe the loss of a species from a specific habitat or from the entire planet?
a) Extinction
b) Endangerment
c) Pollution
d) Eutrophication
33. What is the primary cause of the hole in the ozone layer?
a) Greenhouse gas emissions
b) Chlorofluorocarbon emissions
c) Acid rain
d) Deforestation
34. Which of the following is a consequence of deforestation?
a) Loss of habitat for wildlife
b) Increased soil erosion
c) Release of stored carbon into the atmosphere
d) All of the above
35. What is the main cause of sea level rise?
a) Melting of polar ice caps
b) Expansion of seawater due to global warming
c) Land subsidence
d) All of the above
