TeXes Science Practice Test

In an experiment with meat in two jars, what was the manipulated variable?

1. The type of meat used.

2. The temperature of the jars.

3. The presence of gauze covering one jar.

4. The number of jars used.

The correct answer is: The presence of gauze covering one jar.

In an experiment involving two jars with meat, the manipulated variable is the presence of gauze covering one jar. This variable is specifically altered to observe its effect on the outcome of the experiment, such as determining how it influences the decomposition process or the presence of microorganisms. By changing the gauze covering, the researcher can examine how it impacts the conditions inside the jars and the results, which is the essence of a manipulated variable. The other aspects, like the type of meat, temperature of the jars, or the number of jars, may influence the results but are generally considered controlled variables in such an experiment, as they remain consistent to ensure a fair comparison.