I personally am not 100% sure but my guess would be SAID as it is the only word showing an action.
Answer:
4
Explanation:
I am guessing it's for wheels
I think its A The window-curtain
Participles are verb forms which look like verbs + suffix -ing. So having that in mind, the participle in the sentence above is the word standing.
Participles function either as adverbs (when they modify verbs), or as adjectives (when they modify nouns). In this case, the participle acts as an adjective, modifying the word child.
The subject in this sentence is 'Charles Darwin' which goes before the main verb 'studied'