On a summer day at the equator on mars the temperature never rises higher than 50

TRUE

Explanation:

At the equatorial region of Mars, the temperature on a summer day, usually rises up to an average of about 20°C during the day-time and up to - 70°C during the night time.

This large temperature fluctuation of Mars is due to the presence of a thin atmosphere that is relatively much thinner than the atmosphere of earth. The atmosphere of Mars is primarily comprised of Carbon dioxide (CO₂) and there is high moisture content in the atmosphere, which could allow life to be habitable.

Thus, the above given statement is true.