Answer:
Since sea urchins are picky, they are used as indicator organisms in public aquariums to determine if the system is functioning properly. This is because they are very "picky" about water quality. If the water is contaminated, the sea urchins will be the first to show signs of stress, spines laying down or falling off. Do use an aquarium filter and do clean up the day after feeding. Any metal exposed to the seawater will corrode and poison the tank. A dying sea urchin will often spawn out and rot out, causing the others in the tank to spawn and die as welll.
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This might help
Jatropha<span> plant seeds which are very rich in oil</span>
        
             
        
        
        
Answer:
(of a substance) become concentrated inside the bodies of living things.
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Answer:
(Choice B )
Explanation:
Neurons and muscle cells contain the same proteins, but the cells are different due to their locations in the body.