The answer is stone. hope this helped!
Answer:
The most important cost of WW1 were human lives, as millions of people died during the war and later from many diseases.
Explanation:
WW1 was the most brutal war until then, which devastated European continent.
Although, material costs were enormous, human casualties were even greater.
Only nine millions who died in the war, millions who were wounded and deeply hurt, many families, even many countries devastated.
C. Citizens and their government agree to enter a social contract.
