b. Polar covalent bonds. The polar N-H bonds hold the NH3 molecules together. They are <em>intramolecular forces</em> of attraction <em>within a molecule</em>.
All the other options are <em>wrong</em>. They are <em>intermolecular forces</em> — the attractive forces <em>between different molecules</em>.
Answer: wait im gonna search some info.
Explanation:I come back with an asnwer for you
These could all go either way, hardness and other special properties are what I'm guessing would be the most accurate in determining the kind of material.
luster, cleavage, streak, and color can all be affected by other factors. but I guess cleavage would also be accurate. so I guess hardness special properties and cleavage would be the most reliable.