What were two developments that the Chinese people kept secret for?

explanation:

with the profits from the european sales, merchants purchased europe's manufactured  goods, including tools and weapons. then the merchants shipped those manufactured  goods, along with the  american  sugar and rum, to west africa where they were bartered for  slaves.

the answer is d. amendments.

answer; the parasympathetic nervous system;

answer; can have a long term impact on the newborn;