Which statement is not associated with dark matter?

• A. It emits detectable light
• B. It contributes to galaxy rotation curves
• C. It interacts gravitationally
• D. It is non-luminous

Answer: (A)

Dark matter is invisible because it does not emit, absorb, or reflect light in a detectable way. That’s why a statement about emitting detectable light doesn’t fit dark matter. The other properties fit: dark matter adds to a galaxy’s mass and helps explain the observed rotation curves, it interacts gravitationally just like any mass, and it is non-luminous, meaning it doesn’t shine. Observations such as flat rotation curves and gravitational effects on light from background objects all point to a gravity-dominated, non-emitting form of matter.