GEO 2020Q17
Q: The biological oxygen demand (BOD) of unpolluted river water is:
(a)10 – 20 mg O₂/dm³/5 day.
(b)5 – 10 mg O₂/dm³/5 day.
(c)less than 5 mg O₂/dm³/5 day.
(d)more than 20 mg O₂/dm³/5 day.
Correct Answer: (c)
Detailed explanation coming soon.