Janet wants to know if any form of life, which requires liquid water, has ever existed on Mars. She found these two sources.
Source 1
In order for there to ever have been life on Mars, there had to have been liquid water. Mars has polar ice caps and cloud cover. It has dry river beds and rock types that form only when water is present. It has seasonal weather patterns, volcanoes, and canyons. Scientists at the National Aeronautics and Space Administration (NASA) theorize that if Mars now has or ever had liquid water, microscopic life forms could remain on the surface of Mars.
Source 2
In order to determine if Mars has ever had any form of life, one must know if there is or has ever been liquid water. Mars shows signs of having had water in the past. If this is true, it is possible that microscopictife once existed on Mars. Today, air and temperature conditions would prevent water from remaining for any length of time. Also, ultraviolet radiation from the Sun would not allow anything to live there. If there is any chance that life has ever existed on Mars, many scientists believe it would be evidenced in the form of tiny organisms, or life forms, in protected nooks below the surface of Mars.
Janet wants to know if any form of life has ever existed on Mars.
How do the two sources differ on where evidence of life would be located on Mars?
• 1. Source 1 says that NASA has discovered life on Mars. Source 2 says Mars has had water in the past.
• 2. Source 1 says that moisture from clouds is a water source on Mars. Source 2 says that the water on Mars is in liquid form.
• 3. Source 1 says that evidence of life would be found below the surface. Source 2 says that radiation has destroyed any sign of life on Mars.
4. Source 1 says that any evidence of water on Mars could be found on its surface. Source 2 says the evidence would be found below the surface.