A student investigated photosynthesis in the aquatic plant Elodea. In one method they collected the gas released. In 5 minutes, 3.0 cm³ of oxygen was collected from a 4.0 g piece of Elodea.
Calculate the rate of oxygen production per gram of Elodea. Give the correct unit.
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In another method the student counted the number of gas bubbles released. Counting bubbles is a less valid measure of the rate of photosynthesis than collecting the gas. Explain why.
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