Local conditions such as heavy rainfall or the removal of plants may limit the amount of nitrogen, phosphorus, or calcium available to a particular ecosystem, but the amount of carbon available to the system is seldom a problem. Why?

• A. Organisms do not need very much carbon.
• B. Plants can make their own carbon using water and sunlight.
• C. Plants are much better at absorbing carbon from the soil.
• D. Symbiotic bacteria help plants capture carbon.
• E. Many nutrients come from the soil, but carbon comes from the air.

Answer: (E)

Verified step by step guidance

1. Understand that carbon is a fundamental element in biological systems, primarily found in the form of carbon dioxide (CO2) in the atmosphere.
2. Recognize that plants play a crucial role in the carbon cycle through the process of photosynthesis, where they convert carbon dioxide from the air into organic compounds using sunlight.
3. Identify that unlike nitrogen, phosphorus, or calcium, which are often limited by soil conditions, carbon is abundantly available in the atmosphere, making it less likely to be a limiting factor in ecosystems.
4. Acknowledge that the availability of carbon is not dependent on soil conditions, as it is for many other nutrients, because it is primarily sourced from the air.
5. Conclude that the statement 'Many nutrients come from the soil, but carbon comes from the air' explains why carbon availability is seldom a problem in ecosystems.