Is there a way to change the entire contents of the buffer to capital letters? Can you think of a way to change just one paragraph?

What will be an ideal response?

First mark the whole buffer with CONTROL-X h; then capitalize it with CONTROL-X
CONTROL-U.
To capitalize a paragraph, give the command META-x mark-paragraph (or META-h)
while the cursor is on the paragraph you want to capitalize, and then give the
command CONTROL-X CONTROL-U.