The subjects in economic study are households, business companies, the government (the state), and foreign countries. Households offer their "factors of production" to companies. This includes work, land, capital (machines, buildings) and information. They get income which they use to buy or 'consume' goods. Business companies produce and sell goods and buy factors of production from households and from other companies. The state includes institutions and organisations. The state takes some of the earnings from the business companies and households, and uses it to pay for "public goods" like streets or university education, to be available for everyone. The last subject is foreign countries this includes all households, business companies and state institutions, which are not based in one's own country. They demand and supply goods from abroad. The objects in economic study are consumer goods, capital goods, and factors of production. Consumer goods are classified as "usage goods" (for example, toilet paper), as "purpose goods" (for example, a car), and as "services" (for example, the work of a cleaning lady). Capital goods are goods which are necessary for producing other goods. Examples of these are buildings, equipment, and machines. Factors of production are work, ground, capital, information, and environment.