What is a major difference between Roman and Greek religion?

The answer highlighting the use of planetary names for Roman gods is significant due to the way the Romans adapted and integrated Greek deities into their own religious system. While the Greeks had a well-defined pantheon of gods, the Romans often associated their gods with celestial bodies and named them accordingly, such as Jupiter being akin to the planet Jupiter.

This aspect reflects the Romans' practical approach to religion, where they associated gods with various aspects of life and nature. Additionally, the adaptation of gods and their attributes, including the influence of astronomy and astrology, became central to Roman religious practices, showcasing their beliefs' connection to the universe.

In contrast, the other choices present misunderstandings about the distinctions between Greek and Roman beliefs. The Greek pantheon included numerous gods, similar to the Romans, rather than a singular deity. While Greek mythology included tales of heroes, the idea that they worshiped heroes exclusively oversimplifies their rich religious practices that involved the worship of numerous gods as well. Thus, the correct choice captures a unique aspect of how the Romans framed their religious beliefs in relation to astronomy.