Is these correct:

Simple-Dolphins are very intelligent, social creatures.

Compound- Dolphins are very intelligent and social creatures.

Help on these on:

Simple- Katy is thinking she might like to become a marine biologist one day.

That is not a compound sentence.

The last one is not a simple sentence.

Study this site.

http://www.eslbee.com/sentences.htm

Then how do i turn the 1 one into it

Study the site I posted. It explains a compound sentence.

Yes, both of these statements are correct.

In the first statement, "Dolphins are very intelligent, social creatures," it is a simple sentence because it contains only one independent clause. The subject is "Dolphins," the verb is "are," and the predicate adjective is "intelligent and social." This sentence expresses a single idea about dolphins.

In the second statement, "Dolphins are very intelligent and social creatures," it is a compound sentence because it contains two independent clauses joined by the coordinating conjunction "and." The first independent clause is "Dolphins are very intelligent," and the second independent clause is "Dolphins are social creatures." These two ideas are connected by the coordinating conjunction "and."

Regarding the statement "Katy is thinking she might like to become a marine biologist one day," this is a simple sentence. The subject is "Katy," the verb is "is thinking," and the predicate is "she might like to become a marine biologist one day." It expresses a single thought about Katy's current thoughts and aspirations.