A catalyst is a substance that causes or accelerates chemical changes without itself undergoing change.
(A catalyst; is; a substance that causes or accelerates chemical changes without itself undergoing change) (a substance; causes; ) (a substance; accelerates; chemical changes) (itself; undergoing; change)
A catalyst a substance a substance itself
is causes accelerates undergoing
a substance that causes or accelerates chemical changes without itself undergoing change
chemical changes
change