The main physiological difference between rays and skates is?

The main physiological difference between rays and skates lies in their reproductive methods. Rays typically give live birth (ovoviviparous), while skates lay eggs in protective cases known as "mermaid's purses" (oviparous). Additionally, rays generally have a more flattened body shape and longer, whip-like tails compared to skates, which usually have broader bodies and shorter tails. These differences reflect their adaptations to different ecological niches within marine environments.