Why is cellulose considered to be a complex carbohydrate?

Chitin and cellulose are both polysaccharides

Polysaccharide are the complex form of carbohydrates.

A starch molecule is formed when many disaccharide molecules are combined.  Starch is often produced in plants as a means of storing energy. The two other molecules formed when multiple disaccharide molecules are combined are cellulose and glycogen. The cell walls in plants are made up of cellulose. Glycogen is a carbohydrate energy source. 
A disaccharide molecule is formed when two monosaccharide molecules are joined together. Maltose, sucrose and lactose are the most important disaccharides. A monosaccharide molecule is a simple sugar, for example, glucose. 

1. when the tempature rises,your sweat glands and then springs into action making perspiration. some sweat evaporates with your skin taling heat with it.2.some of the blood pumped by the heart travels by your lungs to get rid of carbon dioxide and pick up oxygen.3.saliva produces by, you drinking water which saliva is 98% of. when mucus builds up in your body it also creates saliva as well as, antibacterial compunds.4.when the core body tempature drops, the shivering reflex is triggered to maintain homeostasis. for example: when you get out the pool you start to shiver because it is cold.