Which Two Main Clades Branch from the Most Recent Common

question 62

Multiple Choice

Which two main clades branch from the most recent common ancestor of the eumetazoans?

• A)Calcarea and Silicea
• B)Lophotrochozoa and Ecdysozoa
• C)Cnidaria and Bilateria
• D)Rotifera and Deuterostomia
• E)Deuterostomia and Bilateria

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Definitions:

Chemical Messenger

A substance, such as a hormone or neurotransmitter, that transmits signals from one cell to another.

Neurotransmitter

Chemicals released by neurons to transmit signals across a synapse to another neuron, muscle cell, or gland.

Calcium Channel

Calcium channels are protein-based channels within cell membranes that selectively allow calcium ions to move into or out of a cell, playing critical roles in various physiological processes including muscle contraction, neurotransmission, and gene expression.

Myelin Sheath

A fatty layer that surrounds nerve fibers, providing insulation and increasing the speed of electrical transmission along the neuron.