Which sentence demonstrates correct parallel structure? The meal was not only delicious but also very filling.
The meal was not only delicious and also filled you up.
The meal was not only delicious but very filling as well.

The sentence which demonstrates correct parallel structure is:

A. The meal was not only delicious but also very filling.

Explanation:

Parallelism is the repetition of the same grammatical structure inside a sentence. The use of parallelism makes a sentence sound better and more organized, making it easier to understand.

Among the three sentences we are analyzing here, the one that shows correct parallel structure is the first one. Let's point out the reasons:

- The structure "not only . . . but also . . ." already asks for parallelism. The blanks after each part are supposed to filled in with similar structures;

- "Delicious" is an adjective and, for that reason, we will need another adjective afterwards in order to make it parallel. "Filled you up" can be eliminated here, since it is not an adjective. "Filling" is the correct choice, but the third option places "as well" after it. It is best to use "but also" before it.

they fear for their lives

i think it may be b, i'm not exactly too sure on this. but b seems to make more sense.