How Did the Song Prevent the Khitans from Invading

question 20

Multiple Choice

How did the Song prevent the Khitans from invading?

• A) They expanded the Great Wall.
• B) They launched an invasion against the Khitans before they could attack.
• C) They formed an alliance with the Jin.
• D) They paid the Khitans tribute to prevent attacks.

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Definitions:

Electromagnetism

A branch of physics that studies the interaction between electric currents and magnetic fields.

Solenoid

A coil of wire that acts as a magnet when carrying electric current, often used to control a valve or other components by moving a ferromagnetic core.

Relay

An electrical switch that opens and closes circuits electromechanically or electronically, often used for controlling a high-power circuit with a low-power signal.

Deficit of Electrons

A deficit of electrons occurs in an atom or molecule when it has more protons than electrons, resulting in a positive charge, often referred to as an ionized state.