Answer:
A. amount of food available
Explanation:
An experiment consists of two types of variables, independent and dependent. Value of independent variable is decided by the person doing the experiment and is independent of experimental conditions. Value of dependent variable is dependent on the independent variable. It can not be altered by the person doing experiment.
Here, it is given that mice receive variable amount of food each day and their lifespan is recorded. Since the amount of food is decided already it is the independent variable. The lifespan is expected to depend on the amount of food hence it is the dependent variable.
I think it is transformation but check with others if i am wrong
If enough ejecta (mainly ash) is sent into the upper atmosphere, the dust particles will block solar energy causing a decrease in temperature. This has happened in the past. Look for the year without summer caused by a volcanic eruption.
