In which sentence is the underlined word a present participle? it is exciting to see the raised head of a dolphin in the water! when dolphins are above the water, they are breathing air. having adapted to pressure changes, dolphins’ lungs enable them to dive below the ocean’s surface. swimming dolphins need to break the surface for air every two minutes.

A present participle is formed with the stem of the workd and the suffix -ing and it can have many functions, such as adjective, a part of the verb phrase. 

Here all the stentences have a present participle! Here they are:

It is exciting to see the raised head of a dolphin in the water!
exciting - it can be seen as a present participle or adjective

 When dolphins are above the water, they are breathing air.
breathing - this is definitely a present participle

 Having adapted to pressure changes, dolphins’ lungs enable them to dive below the ocean’s surface.
 here "having" is the participle"

Swimming dolphins need to break the surface for air every two minutes.

here "smimming" is the participle.

So the answer depends on which word was underlined!

Not really sure but wow ur work is hard