Natural water collected from rivers and ponds contain oxygen, carbon (IV) oxide and
Answer Details
Natural water collected from rivers and ponds contains oxygen, carbon (IV) oxide and "oxide" is not a valid option, as it is not a specific substance. Among the given options, neither hydrogen, chlorine, nor sulphur are commonly found in natural water in significant amounts. Therefore, the correct answer is "nitrogen". Nitrogen gas dissolves in water to some extent, and it is a common component of the Earth's atmosphere, making up about 78% of it.