monosaccaharides are single sugar units, containing carbon, hydrogen, and oxygen in a 1:2:1 ratio.
Yes. All types of sugars are. (Glucose, fructose, galactose)
A monosacchride is a simple sugar. Glucose (C6H12O6) is considered to be a monosaccahride. Two monosacchrides make a disacchride.
It can be a Monosaccahride (1 sugar ring), Disaccahride (2 sugar rings), or Polysaccaride (3 or more sugar rings). It could be more specific but I would need to know more about the sugar.