Answer:
the layer of the earth's atmosphere that contains a high concentration of ions and free electrons and is able to reflect radio waves. It lies above the mesosphere and extends from about 50 to 600 miles above the earth's surface.
Explanation:
Change the pH and the enzyme<span> stops working. Increasing the temperature to 60°C will cause a permanent change to the shape of the active site. This is why </span>enzymes<span> stop working when they are heated. We say they have become </span>denatured<span>.</span>
Complex molecules are made up of other elements bonded with carbon. Carbon is able to bond with other molecules so easily because it has four valence electrons.
I would go with the second one cuz
DNA<span> and RNA </span>consists<span> of nucleic acid </span>chains<span> called nucleotides. Nucleotides are </span>composed<span> of three units: base, sugar (monosaccharide) and phosphate. Bases are found in both </span>DNA<span> and RNA. </span>
