Final answer:
The University of Florida's study on the effects of vitamin C on the speed of greyhounds is an experiment because the researchers manipulated variables and controlled conditions. Experiments involve testing hypotheses under controlled conditions to establish cause and effect, unlike observational studies that monitor subjects without altering variables.
Step-by-step explanation:
The investigation conducted by the University of Florida, where greyhounds were given different diets including high amounts of vitamin C to observe their running speed, was an experiment rather than an observational study.
This is because the researchers actively manipulated variables (diets) and controlled the conditions under which the greyhounds were tested. A key characteristic of an experiment is the ability to control conditions and change variables to observe the effects of these manipulations on a particular outcome—in this case, the dogs' speed.
Examples of experiments in biology include testing the effects of an anti-cancer drug on mice, or cognitive learning studies with rats in mazes. H.C.
Blodgett's maze experiments with rats, where different groups received food at different times as motivation, effectively demonstrated cognitive skills in mammals. In experiments, researchers actively change conditions and measure results to test hypotheses and determine cause and effect relationships.
Conversely, an observational study involves monitoring subjects without manipulating variables. For example, studying the relationships between smoking and lung cancer using existing groups of smokers and nonsmokers can only be done observationally, since ethically one cannot subject people to smoke deliberately for the sake of research.