C. Specialized cells may lose the ability to reproduce.
Answer:
The amount of oxygen in the atmosphere would decrease.
Explanation:
If a massive toxic spill kills off half the population of photosynthetic plankton in the ocean. That would mean that only half of the original population of plankton will remain. Photosynthetic plankton consumes carbon dioxide from the atmosphere during photosynthesis to produce energy and releases oxygen.
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