The correct answer is: and.
The word “and” is used to join two or more things together. In this case, it is used to join the two concepts of “mind” and “body”. This is because when one is struck by the realization of being one with nature, they experience a sense of unity between their mind and body. They feel connected to the natural world around them, and they experience a sense of peace and tranquility.
The other options are not as appropriate in this context. The word “for” is used to indicate a reason or purpose. In this case, it would not make sense to say that one is struck by the realization of being one with nature for their mind and body. The word “in” is used to indicate a location or position. In this case, it would not make sense to say that one is struck by the realization of being one with nature in their mind and body. The word “or” is used to indicate a choice between two or more things. In this case, it would not make sense to say that one is struck by the realization of being one with nature or their mind and body.