Constructive interference occurs when which of the following occurs? Two interfering waves have a displacement in opposite directions.
The trough of a wave interferes with the crest of a second wave.
At the point where there are nodes of standing waves.
The crest of a wave interferes with the crest of a second wave.

i'm on my way to history not a mistory.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2

answerdmitry mendeleyev made a workable classification of the elements

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.