Which statement is true about nuclear fusion?
A)
It involves the splitting of a very large atom.
B)
It requires a fission reaction to power it.
C)
It produces lesser energy than nuclear fission.
D)
It powers the atomic bomb.
E)
It does not normally occur in nature.

Which of these is a disadvantage of hydrogen fuel cells? a. engines that use hydrogen fuel are more efficient than gasoline-powered engines. b. the only emission produced by hydrogen fuel cells is water. c. hydrogen fuel is continually available and useful for heating. d. hydrogen fuel is often purified in a process that emits lots of greenhouse gases.