Geomagnetic storms can disturb Earth's ionosphere, causing the models underlying the Global Positioning System (GPS) to produce inaccurate calculations. This illustrates the effect that space weather events can have on the _____ of GPS and other systems that are dependent on satellite navigation.
Which choice completes the text with the most logical and precise word or phrase?
Explanation
Context: Geomagnetic storms disturb the ionosphere and cause GPS models to produce inaccurate calculations. The blank names the property of GPS and other satellite-navigation systems that this effect undermines.
Answer: B) reliability
Why? Inaccurate calculations make the system less dependable, so space weather affects the reliability of GPS — how much its output can be trusted.
Traps:
- A) significance → the passage is about accuracy failing, not importance
- C) extent → nothing about the size or range of the systems
- D) complexity → the systems aren't described as becoming more complicated