Why do adult urochordates (tunicates) lack notochords, even though larval urochordates have them? Larvae use notochords to ________.
A) aid in swimming; adults are sessile and thus no longer propel themselves
B) stiffen their bodies; in adults, the notochord is replaced by a column of bone
C) induce tissue differentiation; in adults, tissue is already differentiated
D) organize their nervous systems; adults' nervous systems are fully developed and do not change

Question

Quizplus · Accepted Answer

Adult urochordates are sessile animals and do not require notochords for swimming, unlike the larvae. In adults, the notochord is replaced by a stiffened tunic that provides structural support.

Why Do Adult Urochordates (Tunicates) Lack Notochords, Even Though Larval