Answer:
A. how changing a variable can affect behavior.
Explanation:
An experiment can be defined as an investigation which typically involves the process of manipulating an independent variable (the cause) in order to be able to determine or measure the dependent variable (the effect).
Hence, an experiment can show how changing a variable can affect behavior.
This ultimately implies that, an experiment can be used by scientists to show or demonstrate how a condition causes or gives rise to another i.e cause and effect, influence, behavior, etc in a sample.
C. loud noise or music because infection and injury do not occur often and aging wouldn't make any sense.
Answer: Another organ, other than the brain, that is shaped specifically to increase surface area is the small intestine which is part of the digestive system.
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Explanation: