Answer:
A rainbow is caused by sunlight and atmospheric conditions.
Answer:
Russia has built the Trans-Siberian Railroad to overcome the Friction of Space.
Explanation:
Russia is the largest country in the world, and on top of it, its territory is stretched by longitude which creates a situation where from the easternmost to westernmost point the distance is incredibly big. As both the eastern and western coasts are strategically very important for Russia, it is crucial that they are connected with infrastructure that will enable relatively fast and cheap transportation and traveling.
The solution came in the form of the Trans-Siberian Railroad. This is the longest railroad in the world, starting from Saint Petersburg, diverging into two lines, one going to Tyumen but before that at Yekaterinburg turning to merge with the other line at Chelyabinsk, continuing to Chita where it diverges again with one line going through Khabarovsk to Vladivostok while the other moving slightly through Mongolia, Harbin in China, and ending in Vladivostok.