Why a mustard seed would not grow at 100 degree C?
The enzyme inside gets denatured
The mustard seed will not germinate because the enzymes will be denatured by the high temperature.
Enzymes are biological big molecules which help in chemical reactions and work as bio-catalysts.
Denaturation is basically a process which destroy the characteristic properties of usually a protein or biological macro-molecule by either heat, or acidic conditions.