The four main systems of the earth are

Iam stuck on this question! 45 points : ) how do increases in temperature affect the density of ocean water? answer choices: (a) density does not change (b) density increases (c) density becomes variable (d) density decreases

Sink holes may eventually for to join a. wide valleys b. zone of aeration c. dripstones d. aquifer

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?