Nicky led a comprehensive lesson on environmental issues, covering deforestation's impacts on water pollution and soil degradation, as well as fish farming methods and their associated challenges. She explained the process of eutrophication and its consequences for aquatic ecosystems, while also discussing the environmental impacts of biofuel production and large-scale deforestation. The lesson concluded with guidance on exam questions and strategies for approaching different question types, emphasizing the importance of understanding key concepts and making connections between environmental issues.