What does a protective layer formed by fungicides help achieve?

Fungicides are specifically designed to combat fungal pathogens that can cause diseases in plants. A protective layer formed by fungicides acts as a barrier on the surface of plant tissues, effectively preventing fungal pathogens from penetrating and infecting the plant. This barrier is critical in safeguarding the plant's health by reducing or eliminating the potential for infection, thereby preserving both the plant's vigor and yield.

When a fungicide creates this protective layer, it allows the plant to grow without the stress and damage that fungal infections can cause, thus contributing to overall plant health and productivity. The other options do not directly relate to the primary function of fungicides; for instance, enhancing light absorption and increasing soil acidity are not goals associated with fungicide application. Similarly, while minimizing water loss is a consideration in plant health, it is not the primary action or benefit of fungicides.