The Roman aqueducts were an important advance in public: A) hygiene
The blastocyst<span> is a structure formed in the early development of mammals. The word Blastocyst comes from the Greek word Blastos which means sprout and kystis, which means bladder or capsule. Blastocyst is associated with the stage of the reproductive cycle 5 days after fertilization. Hope this answers your question.</span>