Final answer:
Adaptive immunity is characterized by its specificity, memory, and is mediated by both B cells and T cells, providing targeted and memory-based immune responses unique to vertebrates.
Step-by-step explanation:
The correct statements about adaptive immunity are that it is specific, has memory, and is mediated by B cells and T cells. Adaptive immunity is indeed specific to pathogens and has a memory component, which provides long-term protection and a swift response upon subsequent exposures to the same pathogen. Moreover, the adaptive immunity system comprises cell-mediated immunity, involving T cells that attack other cells, and humoral immunity, with B cells releasing antibodies to fight off invaders. Unlike innate immunity, adaptive immunity is specific and can recognize and respond to millions of different antigens. It's also important to note that adaptive immunity is only present in vertebrates, making it a more advanced form of immune response unique to this group.