Hydrogen fuel is clean but not cost-effective. true false

Have you seen very many cars on the road that run on hydrogen? I have not. That means that aside from Apollo and all of its many relatives, hydrogen as a fuel is not  used much. The only way I know how to do it to split water apart and that is going to be very expensive.

True.

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.