Correct Answer: Profound

Solution : The correct choice is the second option .

Superficial means shallow or lacking depth, while profound means having great depth, insight, or complexity.

The meanings of the other options are as follows:

• Deviant means departing from usual standards.
• Artificial means made by human beings rather than occurring naturally.
• Opposing means in conflict or competition with someone.

Therefore, the correct sentence is: "His knowledge is profound in nature."