When the body rejects a newly transplanted organ, this is caused by A. the immune system reacting to the presence of the organ.
If a person's body is said to reject an organ, then it means that the body's immune system viewed the organ as a threat and attacked it.
This means that the organ cannot be used by the body because the immune system will act to prevent it from carrying out its duties.
Find out more on organ rejection at https://brainly.com/question/1313114.
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