It has traditionally been thought that all biological functions decline with age, but according to the Naitonal Institute on Aging, certain important capabilities, such as the output of the heard under stress and intellectual vigor, remain essentially unchanged.
(b) the hearts output under stress and intellectual vigor
(c) intellectual igor and the output of the heard under stress
(d) intellectual vigor and the effect of stress on the heart's output
(e) the effect of stress on teh hear's output and intellectual vigor
C is the best among all the answers.
D and E distort the meaning, hence out.
among A,B and C, both A and B sound as if it's the heart's output(or the output of the heart) under stress and intellectual vigor that remains unchanged. Actually it's the two things that remain unchanged - the intellectual vigor and the output of the heart under stress. hence C.
for every person who doesn't try because he is
afraid of loosing , there is another person who
keeps making mistakes and succeeds..