Which sentence is a compound-complex sentence? O Many historians believe a theory that cultures stretching from
India to Ireland can trace their roots back to one ancestor.
O History has repeatedly shown that the ship of state is run best
when its leadership is based on great ability.
O Since Stu likes doing art projects, we put him in charge of making
the gift, and we got a card.
- O The artists of the Renaissance, such as Michelangelo, created
some of the most powerful art in history.

Since Stu likes doing art projects, we put him in charge of making the gift, and we got a card.

Explanation:

Compound-complex sentence is the type of sentence in which its structure is made up of two or more independent clauses and one or more dependent clause.

Independent clauses are those which aren’t dependent, can be referred to as a complete sentence and express a complete thought.

Dependent clause are those which are dependent,can’t be referred to as a complete sentence and doesn't express a complete thought.

the democratic and republican parties

explanation: