ability , capacity ....

Hello dear teachers

I read in one of my books about the difference between these two words ( ability , capacity ) and the writer explained the difference in a way puzzled me a little bit so would please help me in explaining the difference in a simpler way
the writer says :
ability is a more positive quality or attainment than is capacity . a person may or may not have the capacity to learn singing : after study and practice he may or may not have the ability to sing

so please I need you help

salute :up:

please I need you help
I have an exam today so please I need any comment :-( :-(

Capacity can refer to the potential of something- the human brain has the capacity to store information, so all people have the capacity to learn, but not all of us learn successfully to acquire the knowledge required for something. Human beings have the capacity (physical attributes) to swim, but not all people learn, so these don't acquire the ability.

waooooo
thanks alooooooooottttt

I am very grateful ;-) ;-)