Which Time Period Would Hold the Record of the Oldest

question 60

Multiple Choice

Which time period would hold the record of the oldest fossils of multicellular animals, found in mountainous areas of South Australia, and parts of Canada and China?

• A) Edicarian
• B) Devonian
• C) Cambrian
• D) Cretaceous
• E) Ordovician

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Definitions:

Sinoatrial (SA) Node

A group of cells located in the right atrium of the heart that acts as the natural pacemaker, initiating the heart's electrical impulses.

Atrioventricular (AV) Node

A component of the cardiac electrical conduction system located between the atria and ventricles that delays the transmission of electrical impulses to allow for proper filling of the ventricles.

Bundle of His

A collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node to the point of the apex of the fascicular branches.

Myocardial Infarction

A medical condition also known as a heart attack, which occurs when blood flow to a part of the heart is blocked for a long enough time to cause damage or death to heart muscle.