Sorry i would like to help but i dont want to give you the wrong answer
Answer:
What coated the insides of Roman water pipes was mineral deposits.
Explanation:
Back in ancient Rome the water was rich in minerals, that would create a crust inside the aqueducts by deposition, coating the pipes and protecting the water from lead contamination.
Over time, the build-up of mineral deposits can clog the pipes, which requires periodic maintenance, in many cases the coating of the pipes could be accidentally removed.
The last one
Christmas trees are one thing so it needs a comma after trees not Christmas; cozy sweaters are one thing so it <em>also </em>needs a comma after sweater; and that cancels out the first three.
