What is the common name of the group whose members are characterized by endoskeleton and a unique water vascular system?

a. tunicates
b. medusas
c. echinodermes
d. brachiopods

plz

Why are fossils not found in igneous rocks? igneous rocks are made from cooling of lava or magma. igneous rocks are found too deep underground. igneous rocks are too dark in color to contain fossils. igneous rocks are too dense to contain fossils.

What is responsible for the uneven heating between the poles and the equator on any given day

Rarefaction is used for which of the following? a. creating a representative sample b. studying how disease impacts populations c. rediscovering species thought to be instinct d. determining which sea creatures live in an area