Here's why:

* F₂ is a nonpolar molecule: Fluorine atoms have the same electronegativity, so the F-F bond is nonpolar. The entire F₂ molecule lacks a permanent dipole moment.

* London dispersion forces are present in all molecules: These forces arise from temporary, instantaneous fluctuations in electron distribution, creating temporary dipoles that induce dipoles in neighboring molecules. Even though F₂ is nonpolar, these temporary fluctuations still occur.

* Other forces are absent: F₂ doesn't have hydrogen bonding (no hydrogen atoms directly bonded to highly electronegative atoms) or dipole-dipole interactions (due to its nonpolar nature).

Therefore, London dispersion forces are the only significant intermolecular force present in liquid F₂.