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.
3,000 kilijoules.
You go from 300,000 at the first trophic level to 30,000 at the second trophic level, and finally 3,000 at teh third.
Answer:
D. Cell signalling which is released by one type of cell and acts upon a different cell
Explanation:
According to this question, adrenal cells near the kidney releases an hormone called ADRENALINE, which causes the cells of the heart to beat faster. This is an example of CELL SIGNALLING because chemical signals released by adrenal glands causes/triggers a response in the heart cells.
The chemical signal released by the adrenal cells is the ADRENALINE HORMONE, which induces a response in cells that are different from the cells of release (adrenal cells).