Assess students' understanding of how human activities alter the carbon cycle and drive climate change, covering fossil fuel combustion, land-use change (deforestation, agriculture), methane and other greenhouse gas sources, modification of carbon sinks (oceans, soils, vegetation), feedbacks and timescales, measurement indicators (atmospheric CO2, isotopes), and mitigation strategies such as emissions reductions and carbon sequestration; require explanation of mechanisms and evaluation of mitigation effectiveness.