Ontario Grade 9 Science Class Practice Exam 2026 – Your Complete Guide to Exam Success!

The correct answer is A because photosynthesis, cellular respiration, decomposition, and formation of fossil fuels are all key processes in the carbon cycle. Photosynthesis is the process by which plants and other organisms use sunlight to convert carbon dioxide into energy and oxygen. Cellular respiration is the process by which organisms break down sugars to release energy and carbon dioxide. Decomposition refers to the breaking down of dead organisms and other organic matter, which releases carbon back into the environment. Finally, the formation of fossil fuels involves the accumulation of carbon in decaying organic matter over time, which is then trapped deep underground and converted into fossil fuels like coal, oil, and natural gas. These four processes work together to circulate carbon through the Earth's atmosphere, oceans, and land. The other options are incorrect because they do not involve the cycling of carbon through different parts of the biosphere, and instead refer to