What is the only part of an atom that cannot change (either protons, neutrons, or electrons)?

In a reaction (at equilibrium) that makes more moles of gas than it consumes, what is the effect of increasing the pressure?

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this

Which type of fossil does this image depict?