The answer to this question would be: excess fluoride intake
The toothpaste has a high amount of fluoride and will increase the blood fluor level. Excess fluoride intake in children can cause fluorosis which was the brown staining of teeth because fluor is deposited in the growing teeth. Fluorosis can happen in children with <8-year ages.
Mercury Barometer and aneroid Barometer
Answer: The answer is fungus- like protist
Explanation:
Hardness is the answer I believe
