A scientist is studying a species of toad native to the Amazon rainforest. The toad was once abundant in its native region, but in the last 10 years it has become rare. The scientist knows that the bodies of water that the toad uses for breeding have increased in average annual temperature by 4°C over this same time period due to human activities. He hypothesizes that as the temperature of the water increases, the number of tadpoles that reach maturity in the water decreases. To test his hypothesis, he brings four pairs of healthy, breeding, adult toads to his laboratory. He places one pair of toads in each of four environments, which are all designed to replicate the toads' natural environment. Each environment includes a 1,000-liter pool of water and equal amounts of natural plant life. Each environment has an air temperature of 33.0°C. The water temperature, however, varies in each environment, ranging from 26°C (the average temperature 10 years ago) to 30°C (the average temperature today). The scientist intends to allow the toads to breed and then compare the number of tadpoles that reach maturity in each