Final answer:
Ganymede, the largest moon in the solar system, was discovered by d. Galileo Galilei in 1610.
Step-by-step explanation:
Ganymede, the largest moon in the solar system, was discovered by d. Galileo Galilei. It is one of the four Galilean moons, which also include Callisto, Europa, and Io.
These moons were observed by Galileo in 1610 through his telescope, marking a monumental moment in astronomical history and significantly supporting the heliocentric model of the solar system.