<span>It could be a supernova.
The Crab Nebula is the remnants of a supernova explosion which was
observed in the year 1054. The star that exploded was 6000 light years
away and it was still a spectacular sight even from that distance.So its A.Let me know if I helped.
Give me brainliest and stars.
:)
</span>
When two protein chains combine to form an active protein, the structural level is quaternary.
<h3>What is a quaternary structure?</h3>
The quaternary and tertiary structure of a protein is the tridimensional shape of the protein, which involves protein domains.
The quaternary protein structure refers to the different arrangements generated by different protein subunits.
The primary structure of a protein involves its amino acid sequence, whereas the second structure involves protein chains.
Learn more about quaternary structure here:
brainly.com/question/5286438
Answer:
false
Explanation:
Although the majority of the air we breathe is N2, most of the nitrogen in the atmosphere is unavailable for use by organisms. This is because the strong triple bond between the N atoms in N2 molecules makes it relatively unreactive. However organisms need reactive nitrogen to be able to incorporate it into cells.
<span>Most of the people who have no medical
insurance would typically seek medical treatment at low-cost medical clinics.
This seems to be the best or sometimes, the only way they can get affordable
medical care without health insurance.</span>