In recent years, garbage collection has changed dramatically. Twenty-five years ago a crew of up to 4 or 5 workers and 1 truck collected residential garbage. Now collection is often done by one driver and 1 more fully automated truck. What is an explanation for this change?
◦ Firms and municipalities substituted away from a factor whose price was falling (labour) and toward a factor whose price was rising(capital).
◦ Firms and municipalities substituted away from an increasingly expensive factor (labour) and toward an increasingly inexpensive factor (capital).
◦ The marginal product of labour was falling over time while the marginal product of capital was rising.
◦ Over long periods of time, labour is always replaced by capital.
◦ Over long periods of time, capital is always replaced by labour.
Amazing NASA Pictures Collection
Growth of the body and brain is dramatic over the first 2 years.
Population age 65 and over and age 85 and over, selected years 1900-2008 and projected 2010-2050.