After adjusting for inflation, over time the prices of most natural resources have been a. rising, meaning that their supplies are dwindling more rapidly than our ability to conserve them is growing. b. rising, meaning that our ability to conserve them is growing more rapidly than their supplies are dwindling. c. steady or falling, meaning that their supplies are dwindling more rapidly than our ability to conserve them is growing. d. steady or falling, meaning that our ability to conserve them is growing more rapidly than their supplies are dwindling.