During photosynthesis, unused oxygen atoms form oxygen gas (o2) which is released as a waste product. how did these oxygen atoms originally enter the plant?
a. they were part of the atp molecules gathered by the chloroplasts.
b. they were part of the sugar molecules (c6h12o6) the plant brought in for food.
c. they were part of the carbon dioxide (co2) molecules that entered through the leaves.
d. they were part of the water molecules (h2o) pulled in through the roots.

They were part of the water molecules (H2O) pulled in through the roots.

Explanation:

Photosynthesis may be defined as the process by which plants prepare their food with the help of sunlight, carbon dioxide, water and soil. Two reactions involved in photosynthesis are dark reaction and light reaction.

The oxygen is released as a by product in the process of photosynthesis and used by the other organism. The oxygen can enter in the plant body in the form of water. The water is uptake by the roots and move through all of the plant parts.

Thus, the correct answer is option (D).

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