Which three factors limit descriptive and comparative investigations? A.
The way you must write hypotheses
B.
The number of variables you can have
C.
The amount of time or money required
D.
The number of observations you can make
E.
The features of objects that you cannot s

the only real purpose of sputnik 1 was to beat the us into space. we were getting close to launching a useful satellite, explorer 1 - which launched on january 31, 1958. the ussr had to beat that, so they launched sputnik 1 on october 4, 19

+15-35=-20

going in opposite directions