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.
A stem is what keeps the plant together and supports their leaves
B. STEMS
Answer:
All choices are correct
Explanation:
The most well known was a botanist who studies plants too realized that plats,living things are made of cells so most likely the answer would be all living things are made of cells
I hope this helps, I am only in the 7th grade and this was pretty easy to me
