Answer:
are
Explanation:
I think it is are because it makes sence and because if we add a word it would be are
Pure substances- Chemical substance a form of matter having constant chemical composition and characteristic. Mixtures- A material made up of two or more different substances that are not chemically combined
1 is grammatical but 2 is supposed to read as "I am not so rich in the present" not "at present" and 3 is fine.
"At the present" wouldn't make much sense (To me)
Hope that helps :^)
Answer:
life can be boring that's why the world has puppies
