Answer:
d) polyps; calcium carbonate
Explanation:
The Acanthaster planci It is a kind of invasive starfish, which destroys corals: it has poisonous spines and feeds on coral polyps at the expense of the reef.
On the other hand, CO2 reacts with water, forming carbonic acid and reducing the available calcium carbonate, an essential element so that marine organisms, from clams to hedgehogs, can form their skeletons and shells.
Microscopes are easy to use, often inexpensive tools available to almost any health care facility in the world, making them easy to obtain, even in third world countries but not everyone has the skills necessary to use them, so misdiagnosis is a disadvantage. Microscopes can be used to help diagnose a number of different conditions and diseases.
B- false
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