The respiratory system is best described as: a) the system which delivers oxygen to the bloodstream and takes away carbon dioxide. b) the system which provides the ability to burn all nutrients in the cells. c) the system which delivers oxygen directly to cells and takes away carbon dioxide. d) the system which removes wastes from cells and exhales them from the body.

The respiratory system is best described as bloodstream and takes away carbon dioxide

Explanation:

Respiratory system entails the inhalation of oxygen and exhalation of carbondioxide which is useful for plant for production of their food. Every living organisms respires, hence; oxygen is required to sustain life unless death looms

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1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.