Echinoderm Evolution Is Controversial but Most Zoologists Agree That ___________

question 9

Multiple Choice

Echinoderm evolution is controversial but most zoologists agree that ___________ are related and form one clade.

• A)sea stars and brittle stars
• B)sea stars and sea urchins
• C)sea stars and sea cucumbers
• D)sea urchins and sea cucumbers
• E)crinoids and sea urchins

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Definitions:

Oxetanes

Four-membered cyclic ethers with the formula C3H6O, known for their role in organic synthesis, particularly in polymer formulations and drug discovery.

Pyrans

A class of heterocyclic organic compounds characterized by a six-membered ring containing one oxygen atom and five carbon atoms.

Dimethyl Ether

A colorless gas used as a propellant, refrigerant, and solvent, composed of two methyl groups bonded to an oxygen atom.

3-Ethylfuran

A heterocyclic organic compound with the formula C6H8O, featuring a furan ring with an ethyl substituent.