Earth has a vast store of resources and ecosystem services, called natural capital. How can we use our natural capital sustainably? We need to increase our reliance on nonrenewable fossil fuels, since they are the cheapest form of energy. Unselected We don't have to worry about overusing resources, because we will find suitable substitutes. Unselected We must not use resources faster than they are replaced. Unselected Although we depended on natural capital in the past, technology has ensured that most resources are not being used unsustainably. Unselected We should use the cheapest resource we can, because that will produce the maximum economic return