It has traditionally been thought that all biological

now, as you have given the answer, I see why C is correct in comparison with B. The subject in C is Heart, but in B it 's Output. So, the capability of the Heart should be considered.

FYI...OG and PR state that ..don't choose the sentence that has ..'s.. if you can avoid this with some other --better-- choice...

my bad..!

[quote="asandeep"]It has traditionally been thought that all biological functions decline with the age, but according to the National Institute of Aging, certain important capabilities such as, the output of the heart under stress and intellectual vigor, remain essentially unchanged.

A - same
B - the heart's output under stress and intellectual vigor
C - intellectual vigor and the output of the heart under stress
D - intellectual vigor and the effect of stress on the hesrt's output
E - the effect of stree on the heart's output and the intellectual vigor

I believe C is correct. The meaning is: 2 capabilities including output AND interlactual vigor.
A wrong because it misleading output under BOTH stress AND intellectual vigor
B suffers the same problem
D "the effect..." is not capability
E the same as D.

Ya, I see now...option C is the right choice.

Thanks guys

Why is C correct and A not correct?

They say the same things - Orange and Apples to Apples and Oranges.

Please explain.

Thanks,
CJ

Options A and C are not the same. I too was initially confused between the two. Option A says that the "ouput of the heart" is "under stress and intellectual vigor", which is wrong.
Option C correctly says that the important capabilities are "intellectual vigor" and "the ouput of the heart under stress".
hope this helps...

You're right; I certainly hope GMAC doesn't include questions like this one on the GMAT, but we all I know I'm just wishfully thinking.

Thanks for clarification.

BINGO! :-D