Answer:
D. A brown gas produced
Explanation:
When a chemical reaction occur, there are several changes that takes place such as change in color, odor change, formation of a gas, and formation of a precipitate etcetera.
In the given chemical reaction, two colorless gas (NO and O2) react together and form brown gas (NO2). So, the change of gas from colorless to brown gas is the evidence that shows chemical reaction occurred.
Hence, the correct option is "D. A brown gas produced".
Radio telescope picks up the radio spectrum of electromagnetic waves from celestial bodies (just like telescopes like the Hubble pick up visible light – only that radio waves are invisible to our eyes). They are therefore used to detect objects in space that produces radio waves. Examples are quasars and pulsars. Radio telescopes also enable astronomers to be whats beyond gas and dust in space that blocks out most of the visible light spectrum.
The answer would be (C) i believe.
I think it’s the first one
Answer:
Some viruses are hard to treat because sometimes it’s not the virus that makes us sick; it’s our immune system.
Explanation:
