The study of artificial selection by Darwin helped him to establish his theory of evolution via natural selection. One of the animals Darwin examined in detail was the domestic rock pigeon. In the 1850s breeding of pigeons was an ancient past time, thus, Darwin decided to keep and breed the pigeons by himself.
While studying pigeons, Darwin established scrupulous determinations of their skeletons and wondered at the breeds' distinct colors, behaviors, and proportions. He also observed the patterns of inheritance of various features, and he demonstrated that birds of very distinct breeds can, however, generate fertile offspring. Thus, supporting the theory that they all originated from a single species.
A snow crystal appears when water vapor in the air converts directly into ice without first becoming liquid water. ... The exact shape of the final snow crystal is determined by the precise path it took through the clouds. But the six arms all took the same path, and so each experienced the same changes at the same times.
The answer to this is rolling friction
The earth's surface features are constantly changing in a process known as weathering and erosion. Weathering would happen when rocks would break physically like frost shattering while erosion happens when sediments and rocks are moved from one place to another by agents like water, gravity, wind and ice. These two occurrences are the cause of the constant change of the Earth's surface.<span />
