Which statement is true about systemic fungicides?

Systemic fungicides are specifically designed to be absorbed by the plant and then transported throughout its tissues, offering comprehensive protection against fungal pathogens that may reside within the plant's structure. This unique action allows them to target and combat infections that have already entered the plant, making them effective in managing diseases that affect both the exterior and interior parts of the plant.

Unlike contact fungicides, which simply cover the plant's surface and act as a barrier, systemic fungicides penetrate the plant's internal systems. This characteristic also distinguishes them from options that suggest easy wash-off by rain, which is not the case for systemic products that are integrated into the plant's biological systems. Additionally, the effective duration and application frequency of systemic fungicides can vary based on the specific product and environmental conditions, making the notion that they need to be applied weekly too simplistic. Instead, they often provide longer-lasting protection, potentially reducing the need for frequent applications.