<em><u>Answer:Anatomically, respiratory tract is divided into upper (organ outside thorax - nose, pharynx and larynx) and lower respiratory tract (organ within thorax - trachea, bronchi, bronchioles, alveolar duct and alveoli). The discussion is mainly concentrated on the lower respiratory tract and the related physiology.</u></em>
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Becauses the structure above inportant in maintains homeostyasis
During DNA replication, the two strands separate as the hydrogen bonds connecting the parent strands are broken by an enzyme called helicase. In the DNA molecule (double strand) complementary bases are joined by hydrogen bonds; that is; Adenine paired to thyamine and guanine to cytosine; during replication the enzyme helicase separates the double helix by breaking the hydrogen bonds between the complementary bases.
Answer:facilitated diffusion
Explanation: facilitated diffusion us the carrier-mediated Transport of large molecules across the cell membrane using Transport proteins found in the cell membrane.such molecules include glucose,amino acids and ions.the passage across the membrane is from higher concentration to lower concentration