Question

1. what are the characteristics of echinoderms that belong to the echinoidea class?

• covered in spikes and tube feet and lack arms
• covered in spikes and have several tube feet
• covered in spikes, but have no tube feet or arms
• covered in tube feet and have five arms

Explanation:

Echinoderms of the Echinoidea class (e.g., sea urchins, sand dollars) are characterized by a spiny exoskeleton, presence of tube feet for locomotion/feeding, and lack of distinct arms (unlike classes like Asteroidea which have arms). The first option matches: covered in spikes (spiny test), have tube feet, and lack arms. Other options are incorrect: second lacks the "lack arms" detail, third incorrectly says no tube feet, fourth incorrectly says have five arms (echinoidea lack arms).

Answer:

A. covered in spikes and tube feet and lack arms