The waves going to the right from antenna 1 and 2 are D_(1,R)=A sin⁡(kx-ωt) D_(2,R)= A sin⁡〖(k(x-L)-ωt+ϕ_2,0)〗 Write down the sum of the two waves 〖D_(net, R)= D〗_(1,R)+D_(2,R )and the phase difference Δϕ_R= ϕ_2- ϕ_1 between the two waves. On section 17.6 of the book where you will find the trigonometric identity:

co2reflects heat radiation back to earth buning coal and oil emits co2 globe warms

the answer would most likely be c, because if it's a comical piece of information, it may likely not be true, if it's a site that allows anybody to edit the content, it could mean a five year old is typing the info, and if it's a tv show produced by a celeb, it may have a biased opinion.

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )