Final answer:
Yes, fertilization in sharks is always internal. Most species are ovoviviparous, meaning the embryos develop inside the mother's body and are born alive and fully functional.
Step-by-step explanation:
Internal fertilization occurs in sharks. Most species of sharks are ovoviviparous, meaning that the fertilized egg is retained in the mother's oviduct and the embryo is nourished by the egg yolk. The eggs hatch in the uterus and the young are born alive and fully functional. However, some species of sharks are oviparous, where they lay eggs outside of the mother's body, and the embryos are protected by a shark egg case or 'mermaid's purse'.