Acquired immunity is characterized by:

Pathogen specificity and memory

The correct answer is Option (1) - Pathogen specificity and memory.

Acquired immunity refers to the immune response that develops after exposure to a specific pathogen. It is characterized by pathogen specificity, meaning that the immune system recognizes and targets specific pathogens. This specificity is achieved through the activation and proliferation of B-lymphocytes and T-lymphocytes, which are specialized immune cells.

In addition to pathogen specificity, acquired immunity also exhibits memory. This means that once the immune system encounters a pathogen, it "remembers" the encounter and mounts a more rapid and robust response upon subsequent exposures to the same pathogen. This secondary or anamnestic response is characterized by a heightened intensity and effectiveness in eliminating the pathogen.

The development of pathogen-specific memory is crucial for providing long-lasting protection against recurrent infections. It allows the immune system to respond more efficiently to familiar pathogens, preventing or reducing the severity of subsequent infections.