Which Earth sphere is believed to be the primary location where life first emerged?

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

Answer: (B)

Verified step by step guidance

1. Understand the question: The problem is asking about the Earth sphere where life is believed to have first emerged. The options provided are Atmosphere, Hydrosphere, Biosphere, and Lithosphere.
2. Define the terms: The Hydrosphere refers to all the water on Earth, including oceans, rivers, lakes, and underground water. The Atmosphere is the layer of gases surrounding Earth. The Biosphere encompasses all regions of Earth where life exists. The Lithosphere is the rigid outer layer of Earth, including the crust and upper mantle.
3. Recall the scientific evidence: Early life forms, such as prokaryotes, are believed to have originated in aquatic environments. The presence of water is essential for biochemical reactions, such as the formation of organic molecules and the development of cell membranes.
4. Connect the evidence to the options: Since water is a key component of the Hydrosphere, and early life likely emerged in water-rich environments, the Hydrosphere is considered the primary location where life first emerged.
5. Conclude: Based on the evidence and definitions, the correct answer is the Hydrosphere, as it provided the necessary conditions for the origin of life.