Which type of reaction most likely requires energy input?

The endergonic reaction is characterized by requiring an input of energy to proceed. In such reactions, the products have a higher energy level than the reactants. This contrasts with exergonic reactions, where energy is released as the reaction proceeds and the products have a lower energy level than the reactants.

Endergonic reactions are often found in processes like photosynthesis, where light energy is harnessed to convert carbon dioxide and water into glucose and oxygen. The need for energy input in these reactions is a fundamental aspect of various biological processes, as it enables organisms to build complex molecules from simpler ones, essential for growth and maintenance.

The other types of reactions in the options do not require an input of energy. For example, spontaneous reactions occur without the need for added energy, and catalytic reactions involve a catalyst that speeds up the reaction without affecting the energy requirement of the reaction itself.