A. Global Positioning Satellite (GPS) and two-way radio
B. The chronometer and the astrolab
C. The cross-staff and the compass.
D. The chronometer and the compass.
2007-10-15 08:35:21 · 5 answers · asked by bloodyheartb5 1 in Science & Mathematics ➔ Astronomy & Space
Both radio and GPS were invented before 1999, and that counts as part of the 1900s, so I say A.
2007-10-15 08:46:07 · answer #1 · answered by campbelp2002 7 · 3⤊ 0⤋
B. because both of these instruments were implemented greatly in the 1900's while the cross staff was common in the 1600's and compass has been around since who knows when.
2007-10-15 08:46:30 · answer #2 · answered by metalmonkey71 1 · 0⤊ 2⤋
GPS wasnt invented til the 1990s
The compas was around for centuries before 1900.
the only answer left is B, even though i have no idea what an astrolab is
2007-10-15 08:41:28 · answer #3 · answered by nacsez 6 · 0⤊ 2⤋
A.
2007-10-15 09:13:28 · answer #4 · answered by Anonymous · 2⤊ 0⤋
D
2007-10-15 08:42:54 · answer #5 · answered by bonstermonster20 6 · 0⤊ 2⤋