The optimum level of fluoride in drinking water is between
A:-0.6 – 0.9 mg/liter
B:-0.2 – 0.4 mg/liter
C:-0.3 – 0.7 mg/liter
D:-0.5 – 0.8 mg/liter
Answer:D
The optimum level of fluoride in drinking water is between
A:-0.6 – 0.9 mg/liter B:-0.2 – 0.4 mg/liter C:-0.3 – 0.7 mg/liter D:-0.5 – 0.8 mg/liter