Cellular respiration converts the energy of fuel molecules to a form of energy that a cell can use to perform work. in an average day, most adult humans need to consume about 2,000 calories to maintain their health. however, the exact amount of dietary calories a person needs depends upon many factors, including the person's age, physical activity, size, and health. foods that we consume vary greatly in their nutritional content and quality. a large hard-boiled egg, for example, has about 75 dietary calories and contains about 70% of our recommended daily intake of cholesterol. a. molecules that come from the food we eat provide energy for the amazing work that goes on inside of our cells. this energy, stored inside of our food, is a form of . if a person eats one hard-boiled egg and digests the egg fully, cellular respiration will convert most of this energy into . the amount of dietary calories in one hard-boiled egg could raise the temperature of

What can be said about farmers in highly developed countries? a) they have little or no negative impact on the environment. b) they practice subsistence agriculture. c) they are able to incorporate polyculture into their farming practices. d) they utilize organic farming techniques on a regular basis. e) they rely on large amounts of energy from fossil fuels.

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

When plants use sunlight to make food, the energy of sunlight is