Question

which of the following statements are true? (i) carbon exists only in one form in different parts of the carbon cycle. (ii) carbon is released into the atmosphere in the form of carbon dioxide. (iii) increased carbon in the atmosphere in the form of carbon dioxide contributes to the greenhouse effect on earth. statements i and ii statements ii and iii statements i only statements i and iii

Explanation:

• Statement (I) is false as carbon exists in multiple forms like carbon - dioxide, carbonates, and organic compounds in the carbon cycle.
• Statement (II) is true. Respiration, combustion, and decomposition release carbon into the atmosphere as carbon - dioxide.
• Statement (III) is true. Carbon - dioxide is a greenhouse gas, and increased levels contribute to the greenhouse effect on Earth.

Answer:

Statements II and III