Answer:
The barrier functions to regulate the chemical composition of the extracellular fluid surrounding the brain cells.
Explanation:
Blood-brain barrier
It is a very selective semipermeable membrane , hence allow some specific substance to pass via it . This barrier separates the extracellular fluid in the central nervous system and the circulating blood from the brain .
<u>The barrier is composed of the endothelial cells .</u>
Passive diffusion is shown in this system , and allows molecules like the water , glucose , amino acid to pass .
It regulates the chemical composition of the fluid of brain cell .
Control group
Explanation:
The control group usually serves as a reference for comparison during a scientific investigation.
What is a control group?
- The control group is an experimental group not being tested for.
- it does not receive any modification or design from the scientist.
- It is designed as a reference for the main experiment
- Often times, it is isolated from the main experiment and the independent variables cannot influence the outcomes of the experiment.
Learn more:
Controlled experiment brainly.com/question/1621519
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Answer:
papillary muscles
They are muscles located in the ventricles of the heart and particularly associated with anchoring the right and left atrioventricular valves.

The branch of biology that is related to study of animals, their structures, evolution, and other factors is known as <u>Zoology</u> ~
It would be organelles. This is because they are all part of a cell.