An example of a monosaccharide is
fructose
glucose
galactose
all of the above

All of the above.

Explanation:

Monosaccharide may be defined as the sugars that are not further hydrolyzed or that do not give further sugars on hydrolysis. These monosaccharides are sweet in taste.

Glucose, galactose and fructose are monosaccharide sugars as they cannot be hydrolyzed further to give more sugars. These are colorless and water soluble sugars.

Thus, the correct answer is option (4).

allowed for the prediction of the properties of missing elements.