Xylem and phloem fiber cells
Answer:
D) They can increase the reaction rate for a given reaction by a thousand-fold or more.
Explanation:
Enzymes are like catalysts with the only difference that they are bio-molecules. Biochemical/chemical reactions are slow because of 'transition state barriers' which require a lot of energy to overcome so enzymes rather than overcoming transition state barrier provide an alternate pathway for biochemical reactions which require comparatively less energy. Thus presence of an enzyme leads to an increase in reaction rate because alternate pathway which requires less energy makes the rate of chemical reaction rapid by a thousand-fold or more.
Microscopical observations show the presence of simple in structure, abundant, and pervasive microorganisms. Researchers at the time came to the conclusion that there was a life force in the air.
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