DRUG CLASS AND MECHANISM: Rosuvastatin is an oral drug for lowering blood cholesterol levels. It belongs to a class of drugs called HMG-CoA reductase inhibitors, more commonly referred to as  statins ..RUG CLASS AND MECHANISM: Rosuvastatin is an oral drug for lowering blood cholesterol levels. It belongs to a class of drugs called HMG-CoA reductase inhibitors, more commonly referred to as  statins ..
Natural numbers are naturally used for counting apples (and other things) so they are sometimes called counting numbers. Even some animals other than humans can count and add, so they must be natural. Minus two apples isn't very natural so negative numbers are not included.
No apples is a bit abstract so zero is seen as natural mostly by mathematicians and computer scientists, thus it is only sometimes included in the natural numbers. Ratios of natural numbers are perfectly rational. Squares of natural numbers are perfect squares. Square roots of natural numbers are often irrational.