Answer with Explanation:
"Navigators" are people responsible for telling the position of an object in response to its location. It tells which direction the<em> vessel, vehicle or aircraft</em> needs to follow. In order to do this, they need to be equipped with maps. Maps will allow them to function, since it is their<em> "lifeline."</em> This means that <u>navigators relies on maps</u> in order to know more about the different locations in the area. Without maps, <em>they won't be able to know the correct direction from one point to another.</em> This will also render their navigational skills useless.
If you could dig a tunnel right through the Earth you could theoretically free-fall to the centre of our planet in just eighteen minutes. You can’t, of course: such a tunnel would have to tolerate temperatures as high as the surface of the Sun and pressures three and a half million times greater than those at the Earth’s surface.