Yes
you put an s, you put an s at the end
Not only can you, but you must. The word has an s in it.
you just put it in a sentence :S
they put waste into the lakes until the clean-up in the early 90's
It means there is already an "s" at the end of the word
yes
The polar bear's interaction with a watermelon can be amusing.
http://www.google.com/search?hl=en&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=Z0m&q=Define++interaction&btnG=Search
endangered - to be in danger if that helps.... :s
Interact
Social Interaction can be a word.
The Spanish word 'pone' (pronounced PAWnay) = '(he/she/you) put(s)/place(s)'