Attraction And Repulsion Between Magnets

Step 1: Understanding the Question:
The question asks about the primary biological benefit of the Earth's magnetosphere.

Step 2: Detailed Explanation:
The Sun constantly emits a stream of charged particles (ions and electrons) known as the solar wind.
The Earth's magnetic field acts as a shield, creating the magnetosphere. This field exerts a Lorentz force on the incoming charged particles, deflecting them away from the Earth or towards the poles (causing auroras).
Without this field, these high-energy particles would strip away the atmosphere and cause lethal damage to the DNA of living organisms.

Step 3: Final Answer:
The magnetic field protects Earth by deflecting harmful solar radiation and charged particles.