Answer:
Phosphorus has a low melting point because the intramolecular forces holding it together is London Dispersion Forces.
Step-by-step explanation:
London Dispersion Forces (LDF) are the weakest intramolecular forces. You don't need to break the covalent bonds, but rather the Van Der Waals' Forces. If LDF are the weakest forces, then the melting point is low.