How do astronomers use technology to identify characteristics of the crab nebula? a) technology that detects ultraviolet light found hydrogen in the nebula b) technology that detects radio waves identified a pulsar at the center of the nebula c) technology that detects microwaves revealed the behavior or electrons in the nebula d) technology that detects gamma rays measure the distance of the nebula from earth

The answer is; B

This detected radio source, determined to be pulse-like, was identified to be coming from a pulsating star called a pulsar. The charged particle emitted by the rapidly rotating star is emitted as synchrotron radiation in the radio spectrum. The pulsation was discovered to be at the rate of 30 times a second. Crab nebula is a nebula cloud made from a supernova.

The answer is... B) Technology that detects radio waves identified a pulsar at the center of the nebula

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.