What is the primary difference between allopatric and sympatric speciation?

Sympatric speciation relies on genetic drift, while allopatric speciation relies on natural selection.

Allopatric speciation involves geographic isolation, while sympatric speciation does not.

Allopatric speciation occurs rapidly, while sympatric speciation is always slow.

Sympatric speciation occurs due to physical barriers, while allopatric speciation occurs due to behavioral differences.