The tiny hollow air sacs in the lungs where gas exchange takes place are the "a. alveoli". These are the "last stop" on the respiratory tree and are responsible for oxygen exchange.
Genetic code is the term we use for the way that the four bases of DNA--the A, C, G, and Ts--are strung together in a way that the cellular machinery, the ribosome, can read them and turn them into a protein. In the genetic code, each three nucleotides in a row count as a triplet and code for a single amino acid.
A plant fuels its photosynthesis in part by utilizing carbon dioxide. In doing this, it absorbs carbon dioxide to produce oxygen as a waste product, thereby helping to reduce atmospheric CO₂.
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