Biogeochemical Cycles

In case of which one of the following biogeochemical cycles, the weathering of rocks is the main source of release of nutrient to enter the cycle?

Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth? 1. Volcanic action 2. Respiration 3. Photosynthesis 4. Decay of organic matter Select the correct answer using the code given below.

Which of the following adds/add nitrogen to the soil? 1. Excretion of urea by animals 2. Burning of coal by man 3. Death of vegetation Select the correct answer using the codes given below.

Consider the following : 1. Photosynthesis 2. Respiration 3. Decay of organic matter 4. Volcanic action Which of the above add carbon dioxide to the carbon cycle on Earth ?