Question

1. what is the significance of mendels experiments with pea plants? a. they were the first to study dna. b. they established the principles of inheritance c. they focused on animal genetics d. they disproved the theory of evolution 18. what can be concluded if both the control and experimental groups show the same results? a. the independent variable had no effect on the dependent variable. b. the experiment was a success. c. the controlled variables were incorrect. d. the experiment was invalid. 19. what can rapid changes in traits within populations indicate? a. the absence of selection pressures b. the influence of artificial selection c. the stability of the environment d. the effects of natural selection

Explanation:

1. Mendel's pea - plant experiments established the basic principles of inheritance, such as the law of segregation and the law of independent assortment. DNA was not the focus of his work, and his experiments were on plants, not animals, and did not disprove evolution.
2. In an experiment, the independent variable is manipulated in the experimental group but not in the control group. If both groups show the same results, it means the independent variable had no effect on the dependent variable. The success of an experiment is not determined by this alone, and it doesn't mean the controlled variables were incorrect or the experiment was invalid.
3. Rapid changes in traits within populations can be an indication of artificial selection, where humans deliberately select for certain traits. Absence of selection pressures would lead to more stable traits, environmental stability doesn't usually cause rapid trait - change, and natural selection is usually a slower process compared to artificial selection in some cases.

Answer:

1. b. They established the principles of inheritance
2. a. The independent variable had no effect on the dependent variable.
3. b. The influence of artificial selection