Why a zigzag?
Have you ever noticed that when we climb hills we create zigzags? We don’t go straight ahead but go in zigzags. It can mean walking 20 times as far, and still a zigzag is ___FASTER___ than the shortest distance between two points.
Researchers developed a mathematical model ___SHOWING___ that a zigzag provides the most efficient way for humans to go up or down steep slopes. They explain that zig-zagging ___REQUIRES___ less effort.
Do you know Russian rivers? Do you know what the ___LONGEST___ river in Russia is? It is the Volga River. This river is a great source of hydroelectric power. The water from the river ___IS_USED___ for irrigation. Canals link the Volga River to the Baltic and White Seas. The Volga ___FREEZES___ for most of its length for three months each year.
He didn’t need advice
Once Mozart was approached by a young man, who was interested in Mozart’s advice on how to compose a symphony. Since he was still very young, Mozart recommended that he should start by ___WRITING___ ballads.
___SURPRISINGLY___, the young man responded, “But you wrote symphonies when you were only ten years old.”
“But I ___DID_NOT_HAVE___ to ask,” countered Mozart.