VOA慢速英语:Scientists Work to Understand Earth's Magnetic Field

benefit – n. a good or helpful result or effect

component – n. one of the parts of something such as a system or mixture; an important piece of something

navigation – n. the act, activity, or process of finding the way to get to a place when you are traveling in a ship, airplane, car, etc.

mock – adj. done or performed to look like the real thing

reversal – n. a change to an opposite state, condition, decision, etc.

shield – v. to cover and protect someone or something