28. In the 19th century, it _ two or three months to cross North America by covered wagon. The trip - very rough and often dangerous.

a. took / was

(b, had taken / had been

c. took / had been

d. had taken / was

What can piranhas do in minutes?

In addition to surface tension, what's responsible for driving ocean waves?

In Sudan all people live along which river?

This layer of the sun is visible only during a solar eclipse

The most important export of Venezuela is what

How did the kingdoms of Songhai and Benin differ? A. Songhai grew wealthy from the pepper trade, whereas Benin grew wealthy from fishing. B. Songhai grew wealthy from farming, whereas Benin acquired wealth through trade. C.

What is the least perimeter of a rectangle with an area of 32square. ft

Match the heat transfer mechanisms to the correct description of how heat is transported in or from the Earth.

Which force occurs where earths plates are moving apart

In what south american country have hydrolyte geodes been found