On February 18th, 2021, NASA's new rover, Perseverance, arrived on Mars, a neighboring planet in our solar system. During a seven month journey, it traveled 470 million kilometers (300 million miles) to reach Mars. The exploration robot landed in a region called the Jezero Crater. Near the planet's equator, the crater is 45 kilometers wide (28 miles). Perseverance will spend two years searching for evidence of microbial life that could have existed on Mars billions of years ago. Learning more about the composition of Mars can help scientists better understand the planet's history.
Why does the author include the phrase "Perseverance will spend two years searching for evidence of microbial life that could have existed on Mars billions of years ago?"