Solution: The lines in an atomic absorption spectrum are due to1. the presence of isotopes.2. movement of electrons from higher energy states to lower energy states in atoms.3. nuclear transitions in atoms.4. movement of electrons from lower energy states to higher energy states in atoms. 

Problem

The lines in an atomic absorption spectrum are due to

1. the presence of isotopes.

2. movement of electrons from higher energy states to lower energy states in atoms.

3. nuclear transitions in atoms.

4. movement of electrons from lower energy states to higher energy states in atoms.