Concept:The concentration of oxygen in the atmosphere stays balanced because living organisms use it and plants release it.
Explanation:Humans and animals breathe in oxygen from the air.
Green plants release oxygen during photosynthesis, replenishing what is used.
This cycle keeps the oxygen level nearly constant, not decreasing or increasing.
Oxygen is the second most abundant gas in the atmosphere, not the most plentiful – nitrogen is the most abundant.
Oxygen is not a greenhouse gas; greenhouse gases include carbon dioxide, methane, and water vapour.
Increased oxygen does not cause global warming; it is the rise in greenhouse gases that leads to warming.
Therefore, the only correct statement is that oxygen content remains constant due to the balance between consumption and production.
Answer:Option B: Oxygen content in the air remains constant as humans and animals take it and plants produce it.