Which statement is true about a star with a greater shift in its spectrum than another star? a. it is moving slower. b. it is moving faster. c. it is not moving at all. d. it is exploding into a supernova.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.