A change in an organism's body is an internal stimulus, while a change in the environment is an external stimulus. Thus, the correct option is B.
What is the Environment?
An environment may be defined as anything which is present in the surrounding of living entities through which it interacts for various purposes.
There are a lot of alterations in the body of an organism with respect to time. Apart from organisms, a lot of changes have also occurred in an environment gradually and continuously.
Changes in the organism's body are internal so it is called internal stimulus, while alterations in the environment are externally made so they are called external stimulus.
Therefore, the correct option for this question is B.
To learn more about Organisms and the environment, refer to the link:
https://brainly.com/question/13544588
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