Why European nations suffer massive casualties in the wars early battles (world war 1)

What was the name of the theory that said that if one country in a region fell to communism, others would surely follow? 1) domino theory 2) arms race 3) brinkmanship 4) containment theory

Which of the following most likely contributed to the outbreak of world war ii?

Which of the following statements proves that scientific knowledge changed due to the discovery of the fossil of a hadrosaur in north dakota? hadrosaurs were better runners than earlier thought. hadrosaurs had no pattern on their skin as expected. the length of the hadrosaur was shorter than previously thought. the muscular structure of hadrosaurs was less developed than expected.