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

question 7

Multiple Choice

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) organise their nervous systems; adults' nervous systems are fully developed and do not change

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