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.
 
        
                    
             
        
        
        
Copied, I agree with the person above ^ :’)
        
             
        
        
        
The epidermis is the 5 top layers, and the dermis is the 2 inner layers