34. when the top of a volcano collapses into the vent, a is formed.
a. crater
b. neck

Which of the following best describes the purpose of a nation’s boundaries? a. to limit the movement of goods and people b. to make it easier for cartographers to create maps c. to make the movement of goods and people easier d. to prevent other countries from invading territory

The us labor movement began in the a. 1930s b. 1920s c. 1880s d. 1860s select the best answer from the choices provided. a b c d

Choose the correct chronological or of the time periods