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.
The prokaryotic cell lacks a nucleus and membrane bound organelles.
The half-life of a radioisotope is the amon the symbol 42He, the subscript 2 is the mass number for helium and the superscript 4 is the atomic number for helium.