Final answer:
In all echinoderm bilateral larva, the oral side is where the mouth is located, while the aboral side is the opposite side. For example, in the bipinnaria larva of echinoderms like sea stars, sand dollars, and sea urchins, the oral side is where the mouth forms, and the aboral side is opposite to it.
Step-by-step explanation:
In all echinoderm bilateral larva, the oral side is the side where the mouth is located, while the aboral side is the opposite side.
For example, in the bipinnaria larva of echinoderms like sea stars, sand dollars, and sea urchins, the oral side is where the mouth forms, and the aboral side is opposite to it. The oral side is usually characterized by the presence of feeding structures like cilia or mouthparts.
It's important to note that while echinoderm larvae exhibit bilateral symmetry, most adult echinoderms have radial symmetry.