Question

a ____ is the part of the experiment that provides a standard for comparison, so it is the group that is kept the same as the normal conditions.
procedure
theory
variable
control

Explanation:

The description matches the definition of a control group in experiments: it serves as a baseline for comparison by maintaining normal, unchanged conditions to contrast with test groups. The other options do not fit: a procedure is the experimental steps, a theory is a proposed explanation, and a variable is a factor that changes.

Answer:

control