Topic: Fill in the Blank,

Best Answer Explained in Below-:

The statement "Man did not know that the Earth moves round the Sun until it was discovered" emphasizes the nature of knowledge acquisition in relation to astronomical understanding. The term "discovered" implies that this knowledge was not inherent or readily observable; rather, it required investigation, observation, and ultimately, a revelation that changed humanity's understanding of our place in the universe.

The heliocentric model, proposed by Copernicus and later supported by Galileo and Kepler, was a paradigm shift in scientific thought. It moved away from the geocentric view, which placed the Earth at the center of the universe, a belief that had persisted for centuries. The knowledge that the Earth orbits the Sun was not merely created or invented; it was revealed through careful observation and reasoning.

In contrast, the other options—"experimented," "invented," and "demonstrated"—suggest actions that imply trial and error or the creation of a concept. While experimentation did play a role in refining our understanding, discovery captures the essence of uncovering a truth that was previously unknown. Thus, "discovered" is the most fitting choice, as it highlights the significant evolution in human understanding about the solar system.