What percentage of geologic time is represented by the precambrian era?

What was the 1787 constitutional convention? !

Which answer best describes an advantage of shipping goods by canal? a) most towns would rather have canals then noisy railroads b) goods could travel very fast downstream in the canal system c) traveling by boat is a much more relaxing way to transport goods. d) heavy loads of goods could travel by boat more easily then if pulled by horses.

What was the effect of the industrial revolution on the working class ?