Answer:
Explanation:
In 1976, The Viking 1 and Viking 2 probes landed on Mars. For six years they transmitted fascinating panoramic views of the red and rocky soil of Mars back to Earth. Twenty years passed before a third probe landed on Mars. In 1997, the Pathfinder probe landed a miniature vehicle named Sojourner on the planet. The probes operated for three months and sent back large amounts of data on the Martian environment. At the same time, the Mars global surveyor probe was placed in orbit to take an overall portrait of the planet. It supplied hundreds of thousands of bits of information, especially on climatic variations.