(a) A demand schedule is a table which shows the different quantities of a commodity which consumers are willing to buy at various prices at a particular time.
(b) The law of demand states that at a higher price, less is demanded and at a lower price, more is demanded, other things being equal.
(c)(i) Competitive demand: This applies to commodities which can be used interchangeably. Demand for substitute goods is thus competitive e.g Milo and bournvita, meat and fish, turkey and chicken e.t.c
(ii) Derived demand: This is demand for a commodity which is not needed for direct satisfaction, but rather for the production of other goods e.g the demand for labour and other factors of production.
(iii) Joint or complementary demand: This refers to demand for commodities which are needed to together to satisfy a want. There is joint demand for two commodities when they are such that without one, the other cannot satisfy a want e.g car and petrol, torch and batteries e.t.c.
(iv)Composite demand: This refers to the total or aggregate demand for a commodity which has several uses. The composite demand for cassava for instance comprises the demand for cassava for its various uses e.g making garri, for making industrial starch, for making fufu, e.t.c.