Answer:
Make sure all tested rats are the same age.
Offer the same type of food to the rats in each trial.
Explanation:
<em>In order to be able to isolate the effects of one particular variable during a research, all the subjects in each trial must be subjected to the same conditions except the variable whose effects is being isolated.</em>
Hence, Kate must offer the same type of food to the rats in each trial as well as make sure that all tested rats are the same age.
The circuit has to be closed, so B.
If the circuit was open, the flow of energy wouldn't be able to reach the light bulb.
We should stop polluting the rivers and throwing trash all over the place, and cut down less trees, since we are harming the environment for the animals and plants.
The covalent compound for cci4 is carbon tetrachloride
