Which definition best describes a control in an experiment?
Select one:
It is a part of your experiment that changes.
It is a statement that sums up your results for your experiment.
It is a part of your experiment that doesn't change.
It is your explanation for the change that occurs in your experiment.

It is a part of your experiment that doesn't change.

Explanation:

Experiments usually have a group set up to see if the intervention has worked as intended. the group to which change is made is the experimental group while the one to which no intervetion is provided is the control

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: