Imagine that you want to compare a new diet for tadpoles that are reared in the laboratory to the traditional laboratory diet of boiled lettuce. you want to decide if the new diet will be associated with an increase in the average weight of the tadpoles. the new diet is a meat-based commercial fish food. in your experiment you keep all other factors, such as tadpole density, temperature, ph, amount of food, etc., constant. the only difference between your control and experimental groups is the type of food the tadpoles receive. write a null hypothesis for this experiment: write an alternate hypothesis for this experiment: what is the independent variable? what is the dependent variable? would you want to test only one pan of tadpoles fed lettuce, and only one pan of tadpoles fed meat? why or why not? after you weighed your tadpoles at the end of the experiment, how would you determine if the type of diet significantly affected tadpole size?

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.

The transport tubes from food came down the plant are called?

What happens during the experiment stage of the scientific method