Answer: A. All of the answers are correct.
I attached my work and highlighted my answers. Hope it makes sense! please comment back with any questions if anything is still unclear! :)
a) 0.321 ly
b) 0.321 light years is not far in astronomical terms. Alien life would need to transmit at tremendous power in order for their radio transmissions to be detectable. Their radio signal also needs to be stronger than background noise in order to be distinguishable. Therefore it is unlikely that radio transmissions from alien life will ever be detected.
Answer:
Democritus
Explanation:
He called these "uncuttable" pieces atomos. This is where the modern term atom comes from. Democritus first introduced the idea of the atom almost 2500 years ago.
Answer:
infra red radiation is used