Which of the following is/are structural homopolymers?
(a) Starch  
(b) Glycogen 
(c) Cellulose  

(a) Starch: Starch is a complex carbohydrate that is not a structural homopolymer. It is a mixture of two polysaccharides, amylose, and amylopectin, both of which are composed of glucose monomers. Amylose is a linear polymer of glucose, while amylopectin is a branched polymer.

(b) Glycogen: Glycogen is also a complex carbohydrate and not a structural homopolymer. Like starch, glycogen is composed of glucose monomers, but it is a highly branched polymer that serves as the primary storage form of glucose in animals.

(c) Cellulose: Cellulose is a structural homopolymer. It is composed of linear chains of glucose monomers linked by β-1,4-glycosidic bonds. Each glucose unit in cellulose is oriented in the same direction, resulting in a straight and unbranched polymer. Cellulose is a major component of plant cell walls and provides structural support to plant cells.