rotation – n. turning in a circular direction
variability – n. the state of changing often
author – n. a writer of a book or report
view – n. the ability to see something or to be seen
parameter – n. a limit that controls the way something is done
geology – n. the study of rocks and soil and the physical structure of the Earth
boring – adj. not interesting
option – n. a choice or possibility
decade – n. a period of 10 years
standard – n. a level of quality or behavior