What are hydrogen bonds caused by?

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.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.

lunar landing mission. apollo 11 was the first manned mission to land on the moon. the first steps by humans on another planetary body were taken by neil armstrong and buzz aldrin on july 20, 1969. the astronauts also returned to earth the first samples from another planetary body.

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