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:

Echinoids (class Echinoidea, e.g., sea urchins, sand dollars) have a spiny exoskeleton (test), tube feet for movement/feeding, and lack distinct arms (unlike starfish). Let's analyze each option:

• First option: Matches echinoid traits (spikes, tube feet, no arms).
• Second option: Implies arms (since "several tube feet" alone doesn't rule out arms, but echinoids lack arms).
• Third option: Echinoids do have tube feet, so this is wrong.
• Fourth option: Echinoids lack arms (and "covered in tube feet" is inaccurate; they have spikes with tube feet pores), so this is wrong (describes starfish-like echinoderms).

Answer:

A. covered in spikes and tube feet and lack arms