What two instruments made navigation much easier in the 1900s?

Global Positioning Satellite (GPS) and two-way radio
The chronometer and the astrolab
The cross-staff and the compass.
The chronometer and the compass.

Question

What two instruments made navigation much easier in the 1900s?

 Global Positioning Satellite (GPS) and two-way radio
 The chronometer and the astrolab
 The cross-staff and the compass.
 The chronometer and the compass.

anonymous · Answer

@thomaster

anonymous · Answer

@Luigi0210

luigi0210 · Answer

Well I'm pretty sure they didn't have GPS in the 1900s xD

luigi0210 · Answer

Have you tried making any guesses?

anonymous · Answer

i just found something @Luigi0210 that i think answers the question

anonymous · Answer

@Luigi0210  this is what it is Radio was developed in the early 1900s. By the mid 20th century, radio direction finding using beacons was common. Using the science of the 1920s, developments during World War II in sonar andradar made these available to large vessels and then to anyone, in the late 20th century, due to electronic miniaturization

anonymous · Answer

so due to this i think it is GPS and radio

anonymous · Answer

yep i got it right it is GPS and Radio

anonymous · Answer

thanks for the help

luigi0210 · Answer

Oh, yea, those others existed before the 1900s, sorry, but nice job ~