Which term is represented by the root 'astr/o'?

The root 'astr/o' is derived from the Greek word for 'star.' This root is often used in medical and scientific terminology to indicate something related to stars or celestial bodies. For example, terms like "astronomy" (the study of stars and celestial phenomena) and "asteroid" (small bodies that revolve around the sun, primarily between the orbits of Mars and Jupiter) incorporate this root to convey their meanings related to stars.

In this context, the answer indicating 'star' as the term represented by 'astr/o' is accurate, as it directly aligns with the fundamental meaning of the root. The other options do introduce celestial concepts, but they do not share the same direct etymological link to the term indicated by 'astr/o.' For instance, 'space' and 'sky' refer to broader areas or environments where stars can be found but do not specifically pertain to the celestial bodies themselves. 'Planet' refers to a specific type of astronomical body that orbits stars but does not encompass the broader category that 'astr/o' implies. Thus, 'star' is indeed the most precise term associated with the root 'astr/o.'