Which radioactive isotope is often used as a tracer to study organic reaction mechanisms?

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

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

Which description best characterizes the motion of particles in a solid?