Not necessarily because cells them self don't actually contain cells
Essentially, a control variable is what is kept the same throughout the experiment, and it is not of primary concern in the experimental outcome. Any change in a control variable in an experiment would invalidate the correlation of dependent variables (DV) to the independent variable (IV), thus skewing the results.
Answer: solar radiation
Explanation: Energy released from the Sun is emitted as shortwave light and ultraviolet energy. When it reaches the Earth, some is reflected back to space by clouds, some are absorbed by the atmosphere, and some is absorbed in the Earth's surface Shortwave radiation reflected back to space by clouds.
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