Why was Saudi Arabia fearful of Iraq in 1990? Iraq moved its troops to the border that Saudi Arabia shared with Kuwait
Saddam Hussein had threatened to invade Saudi Arabia.
Iraq had threatened to invade the United States.
O Saudi Arabia was a smaller, more vulnerable country than Kuwait

Saddam Hussein had threatened to invade Saudi Arabia.

Explanation:

Saudi Arabia was fearful of Iraq in 1990 because Saddam Hussein had threatened to invade Saudi Arabia. Further explanation: The Iraqi leader Saddam Hussein rose to a powerful position in 1979 prior to which he has served as the de facto ruler of Iraq for a few years.

the name of the theory is landmass theory.