Answer to Question 1
Perfect competitors sell homogeneous products, while monopolistic competitors sell slightly differentiated products. Firms in an oligopoly sell either homogeneous products or differentiated products. However, a monopolist sells a unique product.
Answer to Question 2
a. Net exports of goods and services equals the value of exports of goods and services, 998 billion, minus the value of imports of goods and services, 1,252 billion, or -254 billion.
b. GDP equals the sum of consumption expenditure, 6,258, plus investment, 1,623, plus government expenditure on goods and services, 1,630, plus net exports, -254, or 9,257 billion.
c. The value of total production equals the value of GDP, so total production was 9,257 billion in 1999.