The part of the experiment against which results are compared is
independent variable
dependent variable
control
constant
hypothesis

Control

Explanation:

The control is the variable that you don't change. Like, imagine you're doing an experiment and are trying to figure out how much of a faster growth rate occurs with fertilized plants. You will compare the fertilized plant to the unfertilized one, which is the control, to see the difference the fertilizer made.

Hope this helped :)

wher is the rest of the question

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.