Complex sentence: Bounce Rock is a football-sized primarily pyroxene rock found within the Margaritifer Sinus quadrangle (MC-19) region of the planet Mars, this object was discovered and observed by the Mars Exploration Rover "Opportunity" in April 2004.
Split into simpler sentences: Bounce Rock is a football-sized primarily pyroxene rock found within the Margaritifer Sinus quadrangle (MC-19) region of the planet Mars. It was discovered and observed by the Mars Exploration Rover "Opportunity" in April 2004.