If an objects volume decreases but the mass stays the same why

Rocks, as they are compressed, begin forming mountains above the earth's surface when two continental plates converge. the continental crust increases in depth as the mountains grow above. the himalayan mountains formed at a convergent plate boundary in this manner. the rocks are smashed together causing them to due to the intense heat and pressure from the colliding plates and eventually forming rock. a) melt; igneous b) layer; sedimentary c) recrystallize; metamorphic d) melt into the earth's interior; metamorphic

Displacement is the slope of a velocity vs. time graph a. true b. false

Calculate the ph of a .10m nh4cl solution. the kb value for nh3 is 1.8×10^-5