Choose the best answer. What is one difference between arthropods and echinoderms?

A) Arthropods have exoskeletons, but echinoderms have endoskeletons.
B) Arthropods have jointed legs, but echinoderms have straight legs.
C) Echinoderms have spiny skin, but arthropods have soft bodies.
D) Arthropods have body segments, but echinoderms only have a skeleton

Epinephrine is a hormone released from the adrenal gland of the body, most often in a stressful situation. it is known as the "fight-or-flight" hormone. one way that it causes a response in the body is to activate receptors on muscle cells. where are these cellular receptors located? a. on the cell membrane b. in the nucleus c. on the cell wall d. around the mitochondria

The energy available as a result of the motion of a body is called energy. -potential -gravitational -kinetic -chemical

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