Answer:
The need for continental time zones stemmed directly from the problems of moving passengers and freight over the thousands of miles of rail line that covered North America by the 1880s. Since human beings had first begun keeping track of time, they set their clocks to the local movement of the sun.
Answer:
c.
Explanation:
They work by killing the bacteria or slowing down its growth, they achieve this by attacking places like the wall or coating the surrounding bacteria.
Chemical digestion involves breaking down the nutrients into smaller cells
Physical digestion is using physical movements such as chewing and swallowing
