To reproduce (asexually). Most unicellular organisms only live for mere hours. The best bet for the species to survive and thrive as a whole is for them to reproduce, or replicate.
we are not "made of stardust" we just are 40% stardust(an impressive amount seeing as the stardust atom is heavier than normal atoms).
<span>Compare: both RNA and DNA have 3 nitrogenous bases: Adenine Cytosine and Guanine. Also b</span>oth have a phosphate groups in their nucleotides<span>
Contrast: </span>RNA is a polymer with a ribose AND a phosphate backbone. It has four different nitrogenous bases: adenine, guanine, cytosine, and uracil.
DNA<span> is a long polymer with deoxyriboses AND phosphate backbone. It also has four </span>different<span> nitrogenous bases: adenine, guanine, cytosine and thymine.
</span>
Hope this helps
Lead.
"Due to insufficient water treatment, lead leached from water pipes into the drinking water, exposing over 100,000 residents to elevated lead levels."
b) some bacteria reduce nitrate ion
