<span>The types of effects that the surgery had on the rats were documented with their bar-pressing behavior. The differences and changes from the injections effected the rats in certain ways. The location of the injection and which types that was more pleasurable for the rat is something that needs further investigation.</span>
The red liquid that circulates in the arteries and veins of humans and other vertebrate animals, carrying oxygen to and carbon dioxide from the tissues of the body.
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Pls. mark as brainliest
Addiction is most likely the answer.
