difference between apply #'mapcar and mapcar

Hallo,
It is strange for me. What is difference between :(apply #'mapcar fn1 
(mapcar fn2 list)) and (mapcar fn1 (mapcar fn2 list))
For example:
12. Break [13]> (apply #'mapcar #'list (mapcar #'cdr '((1 2 3) (a b c) 
(e d f))))
((2 B D) (3 C F))

13. Break [14]> (mapcar #'list (mapcar #'cdr '((1 2 3) (a b c) (e d f))))
(((2 3)) ((B C)) ((D F)))

Why do these 2 applications return different results? What roles does 
"apply" here play?  Is it permitted that 2 funktions (#'mapcar and #'cdr 
) follow "apply"?

Thank you
Greetings
Xu