Answer:
1. According to Science.org, "Roman concrete consisted of a mixture of a white powder known as slaked lime, small particles and rock fragments called tephra ejected by volcanic eruptions, and water."
2. Arches and concrete
Answer:what does it say when you click them we won't know unless we can see?
Explanation:
Need help please I can't fail it
Answer:
B?
Explanation:
i'm sorry if you get it wrong
The other guy is wrong. I am a proffesional teacher at Cambridge and the answer is C.