This document contains an assignment for an Environmental Studies course, asking students to define key terms related to the environment and ecosystems, explain different types of ecosystems like forests and rivers, and describe concepts such as food chains, energy flow, and sustainability. Students are to write short responses for 11 questions focusing on multidisciplinary nature of environment, classification of environmental elements, sustainability, ecosystem definition and function, pond ecosystems, forest ecosystems, scope of environmental studies, river ecosystems, food chains and webs, and grassland ecosystems.