A controlled experiment is one in which: A. the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data.
B. the experiment is repeated many times to ensure that the results are accurate.
C. there are at least two groups, one of which does not receive the experimental treatment.
D. there are at least two groups, one differing from the other by two or more variables.

option c is the correct answer.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.

the potatoes have high sugar concentrations and although these potatoes were different we could seethe effects that their sugar concentrations had in different environments. for example, the potatoes in sample a, were placed in pure water. this created a hypertonic environment and caused the potatoes to draw in water from its surroundings. we saw the opposite happen with the potatoes in sample b when placed in the sodium chloride solution. the potatoes in this case were in a hypotonic solution and therefore lost water to their surroundings.

d we did this already