Josh performs an experiment to see how different brands of fertilizer will affect the growth of tomato plants. the amount of sun, amount of water, & type of soil is the same for every plant. the only thing he changes is the type of fertilizer used on each plant. the fertilizer is the variable. independent dependent constant hypothesis

According to the theory of punctuated equilibrium, at what rate does speciation occur? species change depending on the rate of natural selection. after periods of stasis, new species evolve relatively rapidly. species change slowly and eventually form new species. some species change quickly and others change slowly to balance the overall rate.

Why should the united state be concerned about air pollution in china?

In this case, the statement that people who exercise for an hour may have lower cholesterol levels is .