The correct answer is Very young owls grow slowly.
Here, the adverb is <em>very </em>and the adjective is <em>young, </em>so the adverb is used to modify the adjective, or to show a particular degree of the adjective (how young? very young.).
In the rest of the options, there is only one adverb <em>slowly, </em>and it's not modifying an adjective, but rather the verb.
We appreciate the lives of black people. like by supporting small black owned businesses, and remembering the famous black people who have died
