The two-factor theory of emotion specifically suggests that passionate love can be facilitated by

Physical arousal can facilitate passionate love. It is a naturally occurring and deeply embedded trait found within the DNA of living organisms. The purpose of such is the need to propagate the species in order to ensure its survival in the long run of evolution.

Ifound this on google “according to the findings, a foramen magnum positioned toward the base of the skull is found not only in humans, but in other habitually bipedal mammals as well.” i hope this you for what your looking for