Answer:
It is a compound-complex sentence
Explanation:
To answer this question we need to understand what the definitions are:
A simple sentence has just one independent clause or one complete thought. It has one subject, one verb, and modifiers.
A complex sentence has one independent clause (one subject, a verb, its modifiers, and a complete thought; this sentence can stand alone) and one dependent clause (it doesn't have a complete thought, it depends on the independent clause).
A compound sentence has two independent clauses, they can stand alone, both of them have a complete thought, and they are joined by coordinating conjunctions 'and', 'but', 'or'.
A complex-compound sentence has two independent clauses that can stand on their own without losing a complete thought, and one dependent clause (it can't stand alone; it depends on the independent clause).
So let's look at the given sentence:
<em>This impact was felt from the bottom up, and these contributions to</em>
<em>American institutions may be the ones which most intimately affect the</em>
<em>lives of all Americans.</em>
We can see that the first clause is independent - <u>This impact was felt from the bottom up</u> - it has a complete thought; it can stand alone.
The other clause is also independent - <u>and these contributions to</u>
<u>American institutions may be the ones</u> - it has a complete thought; it can stand alone; it is connected to the other clause with coordinating conjunction 'and'.
The last clause is the dependent clause - <u>which most intimately affects the lives of all Americans</u> - it can't stand alone; it doesn't have a complete thought. To be exact it is an adjective clause, it explains the noun 'contributions' or the pronoun 'one'.
So, we have two independent clauses and one dependent. It is a complex-compound sentence.
I hope it helped you :)
