Given a scientific passage and an answer, generate a question for the given answer.

[EX Q]: Passage: Greenhouse gases include CO 2 , H 2 O, methane, O 3 , nitrous oxides (NO and NO 2 ), and chlorofluorocarbons (CFCs). All are a normal part of the atmosphere except CFCs. The table below shows how each greenhouse gas naturally enters the atmosphere ( Table below ). Answer: greenhouse gases
[EX A]: Co 2 , h 2 o, methane, o 3 , nitrous oxides (no and no 2 ), and chlorofluorocarbons (cfcs) are known as what type of gases?

[EX Q]: Passage: 19.4 Community Ecology Communities include all the different species living in a given area. The variety of these species is referred to as biodiversity. Many organisms have developed defenses against predation and herbivory, including mechanical defenses, warning coloration, and mimicry. Two species cannot exist indefinitely in the same habitat competing directly for the same resources. Species may form symbiotic relationships such as commensalism, mutualism, or parasitism. Community. Answer: symbiotic
[EX A]: Commensalism, mutualism, and parasitism are known as what type of relationships?

[EX Q]: Passage: Osteoporosis is a common age-related bone disease in which bone density and strength is decreased. Watch this video (http://openstaxcollege. org/l/osteoporosis) to get a better understanding of how thoracic vertebrae may become weakened and may fracture due to this disease. How may vertebral osteoporosis contribute to kyphosis?. Answer: osteoporosis
[EX A]:
A common age-related bone disease in which bone density and strength is decreased is know as what?