People who have darker skin have more melanin which is a black or dark brown pigment in the skin. When we are out in the sun our skin produces more melanin, which helps our skin be more resistant in the sun. This is why we tan.
The answer is DNA because genotype is the genes of an organism and genes = DNA.
The answer is the first option.
"They perform well only at very low temperatures."
Despite of advantages of Superconductors such as power and cost efficiency, these conductors have drawbacks. Semiconductors have restricted operation range of operating temperatures. They are required to work at very low temperatures.
Albert, a student researcher, varies the amount of food given to rats in an experiment to measure the effect on their learning behavior. In albert's study, the amount of food given is the independent variable.
An independent variable is under the control of the experimenter. Independent variable does not depend on the other variables involved in the experiment. Since the amount of food is varied, it is not depending on other variables like size of mice, weight, etc.
