How is bohr's atomic model different from rutherford’s model?
electrons in bohr's model are placed in orbits of different energy levels.
bohr's model has a heavy, dense nucleus.
bohr's model has electrons.
electrons in bohr's model are placed in the nucleus.

Option A, Electrons in Bohr's model are placed in orbits of different energy levels.

Explanation:

Bohr’s atomic model gave the concept of discrete energy levels with in an atom while no such concept was outlined by Rutherford. Thus, option A is correct.

While other options are incorrect because of following reasons –

Option B- Both Bohr and Rutherford model proposed existence of dense core of atom which majorly constitutes the mass of atom.

Option C - Both Bohr and Rutherford model proposed existence of electron which revolve around the central mass of  atom

Option D – This concept was proposed neither in Bohr nor in Rutherford atomic model