Do enzymes change during a chemical reaction

enzymes change the Keq for chemical reactions.

Explanation: many enzymes change shape slightly when substrate binds. reactions occur at the "active site" of enzymes, where a precise 3D orientation of amino acids is an important feature of catalysis.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

well we can't tell you because we cant see the time give a screen shot or something.