A population of snails is separated when an eight-lane highway is built. After 50 years, the two separate populations can no longer interbreed. This describes the process of

Read this excerpt from wheels of change by sue macy.that said, it's hard to grasp the full extent of the bicycle's impact on americans in the late 19th century—particularly female americans. imagine a population imprisoned by their very clothing; the stiff corsets, heavy skirts, and voluminous petticoats that made it difficult to take a deep breath, let alone exercise. add to that the laws and social conventions that cemented a man's place as head of the household and holder of the purse strings. how suffocated women must have felt. and how liberated they must have been as they pedaled their wheels toward new horizons.what is the central idea of the excerpt