GEF

12 Introduction UNIT4 | TheGlobal ecosysTem 89 assess yoUR UNDeRsTaNDING Select thebestanswer from thechoicesprovided. 1. Species, suchas seaotters, thathaveahuge impacton theirecosystem if removed areknownas: a. Keystone species b. Biocentric c. Environmental species d. Endangered species 2. Thehydrosphere refers towhichEarth system? a. Water b. Air (gasses) c. Land (rock) d. Life 3. Whichof the following“spheres” is themajor sourceofour fossil fuels? a. Lithosphere b. Hydrosphere c. Geosphere d. Biosphere 4. Whichof thesecycles ismostclosely related to thegreenhouseeffect? a. Carbon b. Nitrogen c. Rock d. Water 5. Bacteria isanessentialcomponentofwhichEarth system? a. Watercycle b. Carboncycle c. Nitrogencycle d. Rockcycle The Assess Your Understanding questions provide the opportunity to test your understanding of the objectives covered in the unit. Certification in Sustainability As part of this course, GEF Institute offers a progressive cer- tificate pathway. Certificates are awarded with successful completion of key units to encourage and motivate you to take steps toward sustainability literacy. In this ever-growing field of study, GEF Institute credentials are acknowledged as an achievement. Earning a certificate demonstrates your under- standing and commitment to sustainability. Principles of Sustainability provides a path toward three levels of certification: Sustainability Apprentice— This certificate demonstrates a well-rounded overview and introduction to sustainability concepts such as the environmental, economic, and social impacts of sustainable choices. This certificate is comprised of the course: Introduction to Sustainability: Its Purposes, Challenges and Requirements located in Unit 1 of of Principles of Sustainability .