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

Why is the development of renewable energy sources important? to decrease reliance on fossil fuels to improve air quality to improve the economic development of LDCs to increase greenhouse gases to increase the wealth of MDCs to reduce habitat

What are the physical and psychological effects of stress?

Which of the following describes the composition of the lithosphere? A. molten iron and granite B. solid iron and nickel C. molten rock D. solid rock Why is the inner core of the earth solid, while the outer core is liquid? A.

Explain how the energy efficiency term "carbon-neutral" can be achieved.

Fossil fuels are considered nonrenewable resources because they a. burn so quickly. c. take hundreds of millions of years to form. b. are in such high demand. d. pollute the air.

What is the western most capital of the west

Is it possible for a mineral to have a prismatic habit without having any cleavage? why or why not? if yes, give an example

Which structure or landform could be a batholith? A. A limestone cavern, such as the popular Mammoth Cave in Kentucky C. A group of mountains, such as the coastal mountains of British Columbia

Vanessa has 3 yards of cotton. She needs 3/4 yard for each skirt she makes. How many skirts can she make?

What is the biggest problem facing the Chesapeake Bay and Puget Sound?