Which of Earth's spheres contains the majority of life on Earth?

• A. Biosphere
• B. Hydrosphere
• C. Atmosphere
• D. Lithosphere

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the concept of Earth's spheres. Earth's spheres are the major systems that interact to support life and include the biosphere, hydrosphere, atmosphere, and lithosphere.
2. Step 2: Define each sphere. The biosphere refers to all living organisms and ecosystems on Earth. The hydrosphere includes all water bodies like oceans, rivers, and lakes. The atmosphere is the layer of gases surrounding Earth. The lithosphere consists of Earth's solid outer layer, including rocks and soil.
3. Step 3: Analyze which sphere directly contains living organisms. The biosphere is specifically defined as the sphere that encompasses all life forms, including plants, animals, and microorganisms.
4. Step 4: Consider the interactions between spheres. While life depends on the hydrosphere (water), atmosphere (air), and lithosphere (land), these spheres primarily support life rather than directly containing it.
5. Step 5: Conclude that the biosphere is the sphere that contains the majority of life on Earth, as it is explicitly defined as the domain of living organisms.