How Many Times Did the Earth's Magnetic Field Switch from North

question 30

Multiple Choice

How many times did the Earth's magnetic field switch from north to south in the last 10 million years?

• A) many - more than 20 times
• B) seldom - less than 5 times
• C) never

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Definitions:

Atrioventricular Valves

Heart valves located between the atria and ventricles, enabling blood flow from the atria to the ventricles while preventing backflow.

Semilunar Valves

Valves located at the exit of both the left and right ventricles of the heart, which prevent backflow of blood into the ventricles.

Ventricles

Ventricles are chambers within the heart that pump blood out to the lungs and the rest of the body, crucial for the cardiac circulation process.

Epinephrine

Hormone secreted by the adrenal medulla in times of stress; also referred to as adrenaline.