Increasing research and development into new forms of renewable energy are most important because a) the price of gasoline is high. b) people like saving the planet. c) current forms of energy are being depleted. d) it is better to keep innovation progressing.

If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes, then a) the planets are microscopic and the stars are millions of miles away. b) the planets are the size of basketballs and the nearest stars are a few miles away. c) the planets are marble size or smaller and the nearest stars are thousands of miles away.

The vegetation that thrives in the tundra is limited to a. mosses, barley, wheat, and corn. b. coniferous trees. c. dwarf shrubs, mosses, lichen, potatoes, and beans. d. mosses, lichen, algae, and dwarf shrubs.

Which of the following types of nonrenewable fuel sources requires the storage of radioactive waste? a. coal b. nuclear c. solar d. oil