Severe or sudden changes in Earth's atmosphere can cause entire species of animals to die. When all of the members of species die out, it is called mutation.

natural selection.

extinction.

revision.

Chronic obstructive pulmonary disease (copd) makes it difficult for the respiratory system to deliver oxygen to the lungs. the scientist wants to use a computer simulation to model how copd affects heart rate and respiratory rate during exercise. she will compare the results of the simulation to the results she gathered in her previous study. which of the following would be an appropriate dependent variable for the new study?