Around 12,000 years ago, a sudden extinction occurred on the temperate grasslands of North America, during which most of the diverse large mammal species died out. A corresponding extinction did not occur on the African savanna, also a temperate grassland, and today it still has diverse herds of large mammals. What possible, but controversial, explanation is thought by some people to explain the North American extinction?
A) Declining habitat or food supply due to climate change B) Arrival of humans in North America C) Receding ice sheets, leading to a climate too warm to support megafauna D) Expanding ice sheets, leading to a climate too cold to support megafauna
A biome contains sagebrush and many types of cacti, as well as rattlesnakes and jackrabbits. It has a hot, dry climate, and many microbes, including bacteria and archaea, that are adapted to live in extreme conditions. Which of these factors would be used to classify this biome?
A) Sagebrush and cacti B) Rattlesnakes and jackrabbits C) Hot, dry climate D) Microbes adapted to extreme environments
A plant has the ability to grow from the base of its leaves, thereby keeping its reproductive buds under the surface and permitting high tolerance of climatic fluctuations. This plant most likely lives in a
A) deciduous forest. B) temperate shrubland. C) grassland. D) tropical rainforest.