Oxygen Concentrations in the Atmosphere First Began Rising About __________

question 42

Multiple Choice

Oxygen concentrations in the atmosphere first began rising about __________ billion years ago.

• A)1.5
• B)2.4
• C)3.1
• D)3.6

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Definitions:

Vagus Nerve

The tenth cranial nerve that innervates many organs, including the heart, lungs, and digestive tract, playing a critical role in the parasympathetic nervous system.

Somatic Motor Neuron

A type of neuron that sends impulses from the central nervous system to skeletal muscle cells, causing them to contract.

Autonomic Ganglion

A cluster of nerve cells that are part of the autonomic nervous system, which controls involuntary bodily functions.

Effector Organ

Any organ or tissue that responds to nerve impulses by performing a specific function, such as a muscle contracting or a gland secreting hormones.