Answer:
That is administered and controlled
Step-by-step explanation:
A variable is the condition or a product that may vary without the influence of any investigator. Such variables can be found abundantly in our daily lives, ranging from air to sunlight. Controlling such variables ensures the limitation of their influence on the outcome of an experiment. In connection to this experiment, the variables that are controlled are the mineral content in the water, the amount of bacteria food, the amount of light and the the constant temperature of 20 degrees C.
If not administered or these variables controlled, the experiment would not clearly explain the impact of caffeine on the heart beat of the water fleas as other variables may have influenced it. Thus variables are controlled to study the singular impact of any agent or effect.
I believe that it's an exhausted bear. Cellular respiration is the way plants and animals receive energy. If the bear is exhausted, it means it's cellular respiration is lacking.
C
by using your cells to make copies of themselves
The respiratory system regulates oxygen flow, and provides regulation for oxygen blood content. Circulatory system plays a roll in providing enough oxygenated blood to the body
Answer:
endothermic reaction
Explanation:
This means it cannot occur without energy (from the Sun).
