Massachusetts Comprehensive Assessment System (MCAS) Biology Practice Test

What role do trees play in the carbon cycle?

1. Trees release carbon dioxide during respiration

2. Trees absorb carbon dioxide for photosynthesis and produce oxygen

3. Trees have no role in the carbon cycle

4. Trees only store carbon in their trunks

The correct answer is: Trees absorb carbon dioxide for photosynthesis and produce oxygen

Trees play a crucial role in the carbon cycle primarily through the process of photosynthesis. During photosynthesis, trees absorb carbon dioxide from the atmosphere and convert it into glucose, a form of energy that they use to grow and develop. This process not only helps to sequester carbon dioxide, reducing its concentration in the atmosphere, but also produces oxygen as a byproduct, which is essential for the survival of most living organisms. The importance of photosynthesis in trees highlights their function as vital carbon sinks. By taking in carbon dioxide, trees help to mitigate climate change by offsetting greenhouse gas emissions. Additionally, as trees grow, they store carbon in their biomass, including their leaves, branches, roots, and trunks, further contributing to carbon sequestration. This storage is a dynamic part of the carbon cycle, as trees also release carbon back into the atmosphere during respiration and decomposition, but their overall impact is significantly beneficial in regulating atmospheric carbon levels.