Systemic Acquired Resistance (SAR) is a plant's immune response that provides long-lasting protection against a wide range of pathogens. When a plant detects an infection, it activates defense mechanisms not only at the site of infection but also throughout the entire plant. This process involves signaling molecules that travel to uninfected areas, preparing them to fend off potential threats. SAR is often triggered by the initial attack of pathogens like bacteria or fungi. The plant produces specific proteins and chemicals, such as salicylic acid, which enhance its ability to resist future infections. This adaptive response helps ensure the plant's survival in a challenging environment.