What scientists understand that earth's interior is liquid?
a) p waves cannot travel through liquids.
b) p and s waves cannot travel through liquids.
c) p and s waves travel through liquids at different speeds.
d) s waves cannot travel through liquids.

Which was not a country that massively built up its navy in the early 1900s? germany china united statesbritain

The us and canadian governments are doing all of the following to combat environmental problems except a. encouraging the use of public transportation b. enacting clean water policies c. requiring emissions testing d. limiting animal populations in some regions

This is a 2017 topographic map of puerto rico in the united states, and i'm sorry that people there have suffered such a disaster. i want to ask, what do the yellow dots and areas represent on this graph? and the blue area and the little blue circle, and the little blue sign that looks like a signal tower, what do they stand for?