The correct answer is option b, that is, the addition of carbon dioxide to the atmosphere.
If the concentration of carbon dioxide upsurges in the atmosphere due to the enhanced rate of outgassing, there will be a constant elevation in the global temperature. The elevating temperature and more dissolved carbon dioxide will result in enhanced weathering of crystal rocks as a consequence of faster rate of reactions and greater acidity.
Choices 1, 2, and 3 all emit carbon dioxide, not enough to destroy the planet, but they still can cause it over a large amount of time, due to Carbon Dioxide being a greenhouse gas. Therefore, the answer is 4. Bicycles do NOT emit any carbon dioxide at all.
Evidence would the fossils they left in the grounds they found.
