A nutrition scientist designs a study in which he assigns 100 people to the treatment group and 100 people to the control group. Although the scientist knows each person's group assignment, the subjects are not aware of their group placement. This is an example of .a. double-blind study
b. uncontrolled study
c. single-blind study
d. biased study

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

This is a typical grassland food web. it is also a small picture of an important cycle on earth: the carbon cycle. describe how the carbon gets into this food web. a) bacteria and fungi, the decomposers, recycle carbon from dead organisms. b) carbon is found in the grass and is passed from one level to the next in this food web. eliminate c) all living things give off carbon dioxide as a by-product of respiration and it is released into the atmosphere. d) plants use carbon dioxide as a reactant in photosynthesis, to make usable chemical energy in the form of a sugar.

Natural resources are any materials that humans obtain from the earth to meet our wants and needs.