Answer:
I think the answer is D because mens testosterone levels are high until the age of 40, then the lower.
Explanation:
That something the is just observation so what you think
A constant factor could be the dose of the drugs and the species of the rats used.
<h3>What is a constant factor?</h3>
In an experiment, a constant factor is one that is not allowed to change al through the experiment. This one must be held as the same and not allowed to vary. A constant factor could be the dose of the drugs and the species of the rats used.
The factor that would be different for the experimental group and the control group the administration of the new drug.
Learn more about experiment:brainly.com/question/11256472
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Answer:
living creaturesss$$ssssssss$ssss$
