How much amount of dissolved oxygen does gravely polluted water consists of?
A. 20 ppm
B. 8 ppm
C. Above 4 ppm
D. Below 4 ppm
Answer:D
How much amount of dissolved oxygen does gravely polluted water consists of?
A. 20 ppm B. 8 ppm C. Above 4 ppm D. Below 4 ppm