Events That Shook Up the World at the Beginning of the 20^th

question 9

Multiple Choice

Events that shook up the world at the beginning of the 20^th century included Sigmund Freud's work on the subconscious mind and the invention of:

• A) the washing machine
• B) the camera
• C) the telegraph
• D) the airplane

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Definitions:

Sodium Ions

Positively charged atoms of sodium, crucial for maintaining fluid balance and transmitting nerve impulses in the body.

Potassium Ions

Electrolytes with a positive charge found inside and outside of cells, essential for maintaining normal cell function including nerve impulse transmission and muscle contraction.

Excitation-Contraction Coupling

Stimulation of a muscle fiber produces an action potential that results in contraction of the muscle fiber.

Troponin-Tropomyosin Complex

A regulatory protein complex in muscle cells that controls the interaction of actin and myosin, essential for muscle contraction.