Question

form a compound sentence.
cheetahs are fast

runners, according to an article in national geographic

runners, but they can only run at top speed for short distances

runners and reach a top speed of around seventy miles per hour

Explanation:

A compound sentence combines two independent clauses with a coordinating conjunction. The first clause is "Cheetahs are fast runners". The option "runners, but they can only run at top speed for short distances" provides a second independent clause ("they can only run at top speed for short distances") connected by "but", forming a compound sentence. The other options either add non - independent clause information (first option) or a phrase that doesn't form a full independent clause with the first part (third option).

Answer:

runners, but they can only run at top speed for short distances