Question

in antarctica, layers of ice more than a mile deep hold a record of the earths weather going back several hundred thousand years. scientists drill out ice cores to study this record. what have they found? theyve learned that one big cause of global warming appears to be carbon dioxide. we are producing more and more of it each year through auto emissions, power plants, and factories. more carbon dioxide is in the atmosphere today than at any point in more than 400,000 years. when the amount of atmospheric carbon dioxide rises, so do temperatures. as a greenhouse gas, carbon dioxide traps heat in the atmosphere. twice as much carbon dioxide is in the atmosphere today as compared to just 50 years ago. scientists say its no coincidence that 10 of the warmest years on record have been in the past 15 years. which of these could help explain why global temperatures are rising? choose one option a scientists are drilling out sections of the ice, causing ice around it to warm up from friction and melt. b as the population increases, so does the number of cars driving on the roads, which produce more carbon dioxide. c renewable forms of energy are being created and used to lower the amount of carbon dioxide in the atmosphere. d factories that produce greenhouse gases are under much stricter regulations now than they were 10-15 years ago.

Explanation:

To explain rising global temperatures, we need a factor that increases carbon dioxide (a greenhouse gas) in the atmosphere.

• Option A: Drilling ice cores is for study, not a major cause of global warming.
• Option B: More cars (from population growth) produce more carbon dioxide. Since CO₂ traps heat, this increases global temperatures.
• Option C: Renewable energy reduces CO₂, which would not explain rising temps.
• Option D: Stricter factory regulations would reduce greenhouse gases, not explain warming.

Answer:

B. As the population increases, so does the number of cars driving on the roads, which produce more carbon dioxide.