1. flying
As the directions state, a participle is a verb. Both flying and headed are verbs. However, headed is used as an action verb in the sentence. It is what the geese are doing. Flying is an adjective describing the geese as "flying by". You should be able to cross out the participial phrase and the sentence will still make sense as in "The geese are headed south for the winter."
2. B. Clapping wildly.
Clapping wildly is the participial phrase. It describes the audience. Option C contains the main verb of the sentence "shouted" so this is not a participial phrase. Option D has an infinitive "to come".
3. cat
The participial phrase in the sentence is "hearing the footsteps of its owner". The cat is what hears the footsteps.
It’s a simile because it said as though
