How have researchers determined that there are four NREM stages of sleep and one REM stage of sleep?

Who wants free brainliest and free points for this drivers ed question! if answered correctly! in the u.s. highway numbering system, north-south routes have numbers that end in a. "0" b. "1" c. a letter d. an even number

Gretta needs a $300,000 mortgage and is offered two choices. the monthly payments for the fixed rate and predicted payments for the arm are shown. adjustable rate mortgage year monthly payment 1-15 $1,610.46 adjustable rate mortgage year monthly payment 1-5 $1,520.06 6-15 $1,728.54 what is the difference between the total costs of the mortgages rounded to the nearest hundred? $8,700 $1,700 $15,800 $5,000

Compare and contrast the environmental consequences of reliance on coal with reliance on petroleum.