Henan Opera originated in the Central Plains (Kaifeng, Henan). It is the largest local opera genre in my country, ranking first among all local operas in the country. Henan Opera was developed continuously, reformed and innovated on the basis of Henan Bangzi.

just finished this it is b. centrifugal force

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation:

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.

i think you may have asked this twice, but i answered one of the