Answer: In the taxonomy of Linnaeus there are three kingdoms, divided into classes, and they, in turn, into orders, genera (singular: genus), and species (singular: species), with an additional rank lower than species. a term for rank-based classification of organisms, in general.
Answer: irregular,inconsistent, unsteady, uneven, shaky, fitful, patchy, variable, varying, changeable, changing, ever-changing, on-and-off, off-and-on, inconstant, erratic, haphazard, unstable, unsettled, spasmodic, sporadic, episodic, intermittent, occasional, unpunctual, wavering, fluctuating, aperiodic, unsystematic, unmethodical, ...
6 trillion miles: a lightyear is defined as being approximately 5.8*10^12 miles, and when rounded: 6,000,000,000,000, or 6 trillion