In Which Vertebrates is Fertilization Exclusively Internal

Question

In which vertebrates is fertilization exclusively internal?
A) chondrichthyans, osteichthyans, and mammals
B) amphibians, mammals, and reptiles
C) chondrichthyans, osteichthyans, and reptiles
D) reptiles and mammals
E) reptiles and amphibians

Accepted Answer

Fertilization is exclusively internal in reptiles and mammals. While some amphibians and fish may also have internal fertilization, it is not exclusive to those groups. Chondrichthyans (cartilaginous fish) and osteichthyans (bony fish) have a variety of fertilization methods, including external and internal.