(i) Monosaccharides: A carbohydrate that cannot be hydrolysed further
to give simpler unit of polyhydroxy aldehyde or ketone is called a
monosaccharide About 20 monosaccharides are known to occur in
nature Some common examples are glucose, fructose, ribose, etc (ii) Oligosaccharides: Carbohydrates 
that 
yield 
two 
to 
ten
monosaccharide units, on hydrolysis, are called oligosaccharides