-Specific tax, is a tax that is defined as a fixed amount for each unit of a good or service sold, such as cents per kilogram. It is thus proportional to the particular quantity of a product sold, regardless of its price.

-Subsidy is a payment to the producers by the government. It lowers the cost of production and shifting supply curve down and to the right. Specific subsidy causes a parallel shift downwards and to the left. Ad valorem subsidy causes a pivoted shift in the clockwise direction

-An inferior good is a good that decreases in demand when consumer income rises, unlike normal goods, for which the opposite is observed.

-Normal goods are any goods for which demand increases when income increases and falls when income decreases but price remains constant

-Luxury goods are products and services that are not considered essential and are associated with affluence. Demand for luxury goods increases as income increases

-Goods are in competitive demand when they are close substitutes of one another. If two goods are close substitutes, a fall in price of one will reduce the demand for the other and vice versa

-Goods that are jointly demanded, for example car and petrol, are complements to each other. The use of one commodity requires the use of the other commodity in order to generate satisfaction. Change in quantity demanded for one commodity is likely to affect the demand for the other.

-Some goods are demanded not for their own sake but because they are used in the production of other commodities. Eg. The demand for factors of production is a derived demand.

-Goods produced together from the same source are in joint supply. The increase in quantity supplied of one commodity leads to an increase in supply of the other good. Eg. Beef and leather

-Competitive supply occurs when increase in the quantity supplied of one good results in a decrease in the supply of the other. This is because the production of goods requires the use of same resources hence the two goods compete for the same factors of production.

-Consumers’ surplus is the difference between the maximum amount that consumers are willing to pay for a given quantity of a good and what they actually pay

-A shortage means that demand for a good exceeds the supply. Hence price naturally increases as consumers are willing to pay more to obtain the good.

-It occurs when there is glut which means that supply of a good exceeds the demand for the same good.

- A situation in which buyers and sellers are on aggregate satisfaction with the current combination of price and quantity if a good bought or sold, and are under no incentive to change their present economic actions. Hence, it is a position of balance which there is no inherent  tendency for change.

-Taste and preferences

-Real disposable income

-Population

-Government policies

-Interest rates

-Exchange rates

-Expectations of the future

-Seasonal changes

-Costs of production

-Price of related goods

-Innovation/State of technology

-Natural factors

-Government policies

-Expectations of future price changes

-The demand curve in downward sloping as in reflects the inverse relationship between price and quantity demanded. As price increases, less consumers are willing to pay the higher price for the same good, hence quantity demanded decreases.

-The effect of a change in price on quantity demanded arising from the consumer switching to, or from, alternative products.

-The effect of a change in real income resulting from a change in the price of the good or service, ceteris paribus.

-Composite demand is the demand for the goods that comes from many sources. (It can be used in many ways by different types of consumers.) For example, the demand of steel derives from multiple appliances, ranging from kitchenware to infrastructure.

-Fixed supply refers to the supply of the production that is restricted and fixed and will not change in accordance to the change in the price level. For example, the fishery industry has its production capacity fixed by natural environment factor.

-A shortage means that demand for a good exceeds the supply. Hence price naturally increases as consumers are willing to pay more to obtain the good

-A glut means that supply for a good exceeds the demand. Therefore, price naturally decreases as producers attempt to erase the excess supply of a good.

-Consumer benefit refers to the individual surplus derived from the consumption of goods and services. It is the economic measure of the difference between what consumers are willing and able to pay for a good or service relative to its market price.

-Producer benefit refers to the producer surplus derived from the sale of goods and services. It is the economic measure of the difference between the amount a producer of a good receives and the minimum amount the producer is willing to accept for the good