The Decline of Cyanobacteria in the Early Cambrian Oceans Was

question 4

Multiple Choice

The decline of cyanobacteria in the early Cambrian oceans was most likely related to

• A)the movement of animals onto land.
• B)the evolution of land plants.
• C)an increase in the number of predatory fish.
• D)an increase in organisms with suspension-feeding mouthparts.
• E)a decline in the number of marine decomposers.

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Definitions:

Molecular Oxygen

A diatomic molecule \(\text{O}_2\) that is essential for respiration in aerobic organisms and acts as the final electron acceptor in cellular respiration.

Electrons

Subatomic particles with a negative charge that orbit the nucleus of an atom.

Positive Charge

An electrical charge with more protons than electrons, resulting in a net surplus of positive electric charge.

Protons

Positively charged subatomic particles found within the nucleus of an atom.