1. England
   the United States
2. Italy

In 1877, Italian astronomer Giovanni Schiaparelli was the first to create a map of Mars. His map showed a system of canali, or canals, on the red planet.

1. Mariner 9 and 10
   Viking 1 and 2
2. Voyager 5 and 6

In 1976, U.S. space probes Viking 1 and 2 became the first of their kind to land on the surface of Mars. These probes found Mars to be a desert planet with reddish rusty color.

1. Southern Highlands
   Eastern Plains
2. Western Plateau

Mars' three regions are called the Southern Highlands, Northern Plains and Polar Regions. The Southern Highlands is an area of heavily cratered, high terrain.

1. Mauna Loa
   Valles Marineris
2. Olympus Mons

The highest mountain on Mars is also the highest mountain in the solar system, a shield volcano known as Olympus Mons that is 16 miles high, 10 miles higher than the largest volcano on Earth.

1. 1,200 miles
   2,400 miles
2. 4,000 miles

The Valles Marineris is a large system of canyons on Mars measuring 2,400 miles, greater than the distance from New York to Los Angeles.

1. -81
   0
2. 2300

While the surface temperature on Mars ranges from -220 to 70 degrees Fahrenheit, the average temperature is -81, or about -63 Celsius.

1. nitrogen
   hydrogen
2. carbon dioxide

About 95 percent of the Martian atmosphere is carbon dioxide. Earth's atmosphere, in contrast, contains less than 1 percent carbon dioxide.

1. Gio
   Sol
2. Tharsis

A Martian day is called a Sol. Mars has a rotational period very similar to that of Earth; a day on Mars is about 24.6 hours.

1. 100,000 years
   4,000,000 years
2. 10,000,000 years

Scientists believe Mars formed by the clumping, or accretion, of small objects in the early solar system, which took about 100,000 years.

1. the Himalayas, a cold, mountainous landscape
   Antarctica, a dry, cold desert
2. an exaggerated Sahara desert, sandy and extremely hot

Mars is a dry, cold landscape where it doesn't rain, most closely resembling the frozen, flat terrain of Antarctica on Earth.