The blank is like a solar panel because both transform the Sun’s energy into a useable form

Chloroplast

Explanation:

Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells. It is like a solar panel that changes sunlight energy into electric energy.

because the vietnam war was fought in an especially brutal and untraditional way

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: