Answer: isotopes
Explanation: I remember this from when I took honors chemistry, they are know as isotopes.
Answer: b) Doppler Effect
Explanation:
Line broadening in AAS, arises due to some effects, which can occur due to a number of factors. The line width broadening effects include: Doppler, Lorentz, Self absorption, and quenching effects.
Doppler effect arises because along the line of observation, atoms will have different components of velocity.