Question

1st attempt
the michaelis constant ($k_m$) of an enzyme is a measure of
choose one:
the energetic favorability of the reaction.
the binding strength of enzyme to substrate.
the rate at which the enzyme converts the substrate to product.
the activation energy.

Explanation:

The Michaelis - constant ($K_M$) represents the substrate concentration at which the reaction rate is half of the maximum velocity ($V_{max}$). It is an indicator of the binding strength between an enzyme and its substrate. A lower $K_M$ value indicates a stronger binding as it means the enzyme can reach half - maximum velocity at a lower substrate concentration.

Answer:

the binding strength of enzyme to substrate.