Answer:
Students who take a PE class and who will be eating sugary snacks before PE.
Explanation:
The control variable (or control group) is an experimental element which is constant or unchanged throughout the course of the experiment.
The option "students who take PE class and who will be eating sugary snacks before PE" will remain unchanged and constant because the whole point of the experiment is to see the effects on students performance in PE after eating sugary snacks.
Hope this helps :)
<span>Soils rich in organic material are always highly fertile.</span>
I think the answer is 90%. According to the recent National institute of Health, Microbes in the human body estimates that 90% of the cells in human body are bacterial, fungal, or otherwise non-human. Despite the arguments that bacteria enjoys a commensal relationship with the humans hosts, only a fraction of the human microbia has been characterized.
Answer:
They allow for automatic biogeographic isolation
