Courtney and kenzie are doing an experiment to determine which fish food gives their fish more energy. they have two fish tanks, each with the same number, size, and type of fish. the tanks are the same size and have identical filters and decorations. they were both filled with store-bought spring water and are cleaned at the same time. when the girls submitted their results to a journal for publication, scientists criticized the experiment.

what about the experiment would need to be changed so that scientists might accept their findings?

a) the fish would need to be fed more food.
b) the tanks would need more fish in each one.
c) there would need to be several more tanks of fish.
d) the tanks would need to have a different type of water.

What two fields of study provide the core information that is used to classify organisms?

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.

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates