What Key Event Happened During the Decoupling Epoch

question 51

Multiple Choice

What key event happened during the decoupling epoch?

• A) Dark energy accelerated the cosmos on to infinity.
• B) Electrons and positrons were created.
• C) Expansion cooled the universe enough that protons could capture electrons in orbit.
• D) Pairs of neutrons and protons were created.
• E) The universe underwent a brief period of very rapid expansion.

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Definitions:

Protostomes

Animals that belong to the Protostomia, one of the major animal clades. Include the annelids, arthropods, and mollusks. Compare with deuterostomes.

Deuterostomes

A major group of animals characterized by their embryonic development, in which the anus forms before the mouth.

Spiral Cleavage

A distinctive spiral pattern of blastomere production in an early protostome embryo. Compare with radial cleavage.

Coelom

The main body cavity of most animals; a true coelom is lined with mesoderm. Compare with pseudocoelom.