When a group of people are linked together by common characteristics such as beliefs or history this is known as

answer; people where able to travel across the u.s.a faster than any other mode of transportation,travel time was about a week,from coast to coast

payments were made after the 1940s.

in the 1980s, a commission held investigations and made recommendations.

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.

spread of christianity