Answer: I think it D if it not don't report me
B, the Arctic Ocean borders Russia only to the North
Answer:
The ancient Greeks and Romans used dated references to eclipses to improve the calendar. They also noted phenomena related to eclipses. The corona seen during eclipses was only identified as a solar phenomenon in the middle of the 19th century.
Explanation:
Answer:
The answer is concrete
Explanation:
Ancient Roman concrete was a mixture of lime mortar, aggregate, pozzolana, water, and stones, and was stronger than previously-used concretes. The ancient builders placed these ingredients in wooden frames where they hardened and bonded to a facing of stones or (more frequently) bricks.