Which of the following statements about dissolved oxygen (DO) and Biochemical Oxygen Demand (BOD) are true?
- DO is necessary for the survival of aquatic organisms.
- Higher BOD indicates higher levels of organic pollution.
- BOD is a measure of the oxygen required for chemical oxidation.
- High DO levels can result in fish kills.
1
1 and 2
2
2 and 4
3
1, 2, and 4
4
2, 3, and 4