Answer:
When two simple sentences are combined correctly to make one longer sentence, we call that sentence a compound sentence. There are three ways to do this.
Explanation:
1. Use a semi-colon:
This program had tremendous success; the seal populations increased significantly.
2. Use a coordinating conjunction ("fanboys") preceded by a comma:
This program had tremendous success, for the seal population increased significantly.
3. Use an adverbial connective preceded by a semi-colon:
•This program had tremendous success; in fact, the seal population increased significantly.