The correct answer is I - 5, II - 1, III - 2, IV - 4. Key Points The biosphere is the narrow zone of earth where land, water, and air interact with each other to support life. It is a relatively thin life-supporting stratum of Earth’s surface. The biosphere is a global ecosystem composed of living organisms (biota) and the abiotic (nonliving) factors from which they derive energy and nutrients. An ecosystem is a community of living and non-living things that work together. The atmosphere is the whole mass of air that surrounds the Earth. It is a blanket of air that surrounds the earth.​ Composition of Air in the Atmosphere: Nitrogen — 78 percent Oxygen — 21 percent Argon — 0.93 percent Carbon dioxide — 0.04 percent The hydrosphere includes water that is on the surface of the planet, underground, and in the air. About 71 percent of the Earth's surface is covered by water, and the oceans hold about 96.5 percent of all Earth's water. Environment means anything that surrounds us. Additional Information Ecology is the study of the interactions between organisms and their physical and biotic environment. The gravitational force of the Earth (Gravity) is 9.8 m/s2. Newton’s law of gravitation states that any particle of matter in the universe attracts any other with a force varying directly as the product of the masses and inversely as the square of the distance between them.