Answer:
It is not A. interest level
It is B ability
Explanation:
The variable is the group that was given caffine, because thats what the doctors manipulated. They possibly altered the natural memory of the participants by giving them caffine. A more specific variable could be how much caffine each participant is given and what time are they given it.
I believe the answer is produces co2
<span>Rainforests are subject to heavy rainfall, at least 80 inches (2,000 mm) — and in some areas over 430 inches (10,920 mm) — of rain each year. In equatorial regions, rainfall may be year round without apparent "wet" or "dry" seasons, although manyforests do have seasonal rains.
Hope this helps. :)
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