There are three domains, and six kingdoms.
Answer:
to indicate the smallest unit of a repeating substance
Explanation:
You can use dimensional analysis to figure this out.
× 
= 3 grams
If done correctly, ml and ml will cancel out, leaving you with grams.
If you don't know dimensional analysis, simply multiply <em>3 ml</em> by <em>1 grams </em>and that should still get you 3 grams.