A mere ………………… impurities make water contaminated with domestic sewage unfit for human use.
A. 0.8%
B. 0.7%
C. 0.5%
D. 0.1%
Answer:D
A mere ………………… impurities make water contaminated with domestic sewage unfit for human use.
A. 0.8% B. 0.7% C. 0.5% D. 0.1%