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.
Hello!
They are called producers because they're able to produce their own food by the process of photosyntessis.
Explanation:
photosynthesis converts carbon dioxide and water into oxygen and glucose.glucose is used as food by the plant and oxygen as a by-product.
cellular respiration convert oxygen and glucose into water and carbon dioxide water carbon dioxide a byproduct and ATP is energy that is transformed from a process.
Https://www.reference.com/science/plant-cells-bigger-vacuoles-animal-cells-6ce1d958f161267a#
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