Some of the techniques used by astronomers to determine the type of galaxy in which we live are:
- radio,
- optical,
- infrared
- x-ray astronomy
<h3>What is Astronomy?</h3>
This refers to the study of heavenly bodies and space and other things that space is made up of.
Hence, we can see that the reason why it is so difficult to determine the shape of our galaxy is that astronomers can only infer its presence from the motions of stars in the galaxy, and a precise shape is difficult to be determined.
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brainly.com/question/1141458
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This is a speed/time graph.
The slope of the graph at each point is the time rate of change of speed
at that point, and THAT's the definition of the magnitude of acceleration.
The slope of the curve is zero at both ' A ' and ' B ', so acceleration is
zero at both of those points.
That seems to be exactly what choice-c says.