Which of the following can astronomers detect if a star is a part of a binary system
(a) the star varies in temperature near the binary
(b)the star wobbles near the binary star
(c)the star has very strong gravity
(d) the star belongs to an open cluster

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.

explanation:

a