Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: Bob pulled a rock out of the ground.  He wanted to examine the thing because he was into geology.   He was also into waterskiing.   He had many what?
interests
hobbies.