Geologic time begins with a very long span called precambrian time. precambrian time ended about 544 million years ago. since then, the basic units of geologic time are, in order from longest to shortest: a) eras - periods - epochs. b) eras - epochs - decades. c) orders - epochs - periods. d) epochs - periods - centuries.

Which pair of sentences is describing the same velocity? a. a car is parked. a car is moving in circles. b. a bus drives 40 miles per hour north. a truck drives 50 miles per hour north. c. a boy walks east at 6 kilometers per hour. a girl walks west at the same speed as the boy. d. valerie rides her bike south at 8 kilometers per hour. owen jogs south at 8 kilometers per hour.