What factor primarily affects the solubility of nutrients in water?

The solubility of nutrients in water is primarily influenced by temperature because it affects the kinetic energy of the molecules involved. As temperature increases, the kinetic energy of water molecules also increases, which enhances the ability of water to dissolve solutes, including various nutrients. A higher temperature generally allows more solute to dissolve, resulting in increased solubility.

While pH, pressure, and concentration can also impact solubility, their effects are not as straightforward as temperature. For instance, pH affects the ionization of some nutrients, thereby influencing their solubility, but this relationship is specific to certain compounds rather than a general rule. Similarly, pressure can affect the solubility of gases in liquids but is less significant in comparison to the influence of temperature on the solubility of solid and liquid solutes. Concentration refers to the amount of solute already present in the solution and is more about the saturation point rather than a factor that directly enhances the dissolution process.

Thus, temperature is the primary factor affecting how well nutrients dissolve in water, making it the correct choice.