Answer:
The variation in attraction of some atoms causes hydrogen bonding
Step-by-step explanation:
Hydrogen bonding is caused by the tendency of some atoms in molecules to attract electrons more than their accompanying atom.
This gives the molecule a permanent dipole moment, it makes it polar, so it acts like a magnet and attracts the opposite end of other polar molecules.
What is hydrogen bonding?
A hydrogen bond is a partial intermolecular bonding interaction between a lone pair on an electron rich donor atom.