Embryology Evidence Practice Test

A student compares embryos at the same stage (Stage 1) for three species: shark, salmon, and human. The images show shark and salmon embryos are very similar in overall shape and have similar gill slit (pharyngeal pouch) appearance, while the human embryo shares some features but is less similar overall. The student claims: “Shark is more closely related to salmon than to human.” Since embryology provides evidence for relatedness, which evidence-aligned statement best supports the claim?

A teacher shows embryo images at the same stage (Stage 2) for three mammals: cat, whale, and horse. The images show the embryos look very similar overall, including similar limb buds and tail buds. A student claims: “Cat, whale, and horse are closely related compared with a frog.” Embryology provides evidence for relatedness. Which prediction would strengthen the student’s claim using embryological evidence (without using genetics)?