How have the historic levels of melanin in human populations changed due to migration? (1 point)
• Humans that produced more melanin became more common as populations migrated away from the equator.
• Humans that produced less melanin became more common as populations migrated toward the equator.
• Humans that produced less melanin became more common as populations migrated away from the equator.
• Humans that produced more melanin became more common as populations migrated toward the equator.
• Humans that produced less melanin became more common as populations migrated toward the equator.
How would reducing low-growing plants from an area impact a population of tortoises with two varieties of neck extension ability: short and long distance? (1 point)
• The proportion of tortoises that could only extend their necks a short distance would increase.
• The proportion of tortoises with the ability to extend their necks a long distance would increase.
• The variety of tortoises that could only extend their necks a short distance would go extinct.
• The variety of tortoises with the ability to extend their necks a long distance would go extinct.
• The proportion of tortoises with the ability to extend their necks a long distance would increase.
In an ecosystem, there are two color varieties within a species of toads: brown and green. Over 50 years, the proportion of the population that is green increases from 20% to 50%. Which statement is the most likely to explain this change? (1 point)
• A disease caused a decrease in the proportion of brown toads.
• Pollution caused a decrease in the proportion of brown toads.
• The environment changed such that green toads can blend into their surroundings better.
• The environment changed such that toads that can jump higher into the trees to survive better.