Answer:
I hope this helps
Explanation: Physical changes do not change a sbstances identity, it can consist of changes in color, size, etc.
Chemical changes on the completley changes the chemical makeup of a substance. Chemical changes can consist of combustion, corrosion, etc.
B and D are not true of Bohr's model of the atom.
Bohr's model assumed that electron of a hydrogen atom travels in discrete elliptical orbits (not circular, as you have probably been taught) whose size depended on the allowed energy levels of the electron.
Answer:
Stopwatch
Stopwatch is a time measuring tool.
Answer:
I think it's lead (pb). Hope this helps.