Match the environmental remediation method to its description.
soil vapor extraction
air sparging
bioventing
natural attenuation
Air is bubbled through groundwater to
remove volatile organic pollutants.

Natural processes break down the
pollutants.

Air is circulated through perforated
pipes in the contaminated soil.

Air is pumped into or out of soil to
supply oxygen to microbes.

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?