Final answer:
T cells are immune cells that carry out important functions in the adaptive immune response. Killer T cells destroy infected or cancerous cells, while helper T cells manage immune responses. Different subtypes of T cells can be formed, and memory T cells provide long-lasting protection against viruses.
Step-by-step explanation:
T cells are a type of immune cell that play a crucial role in the adaptive immune response. When activated properly, T cells can carry out several important functions. Killer T cells destroy cells infected with pathogens or cancerous cells, while helper T cells manage immune responses by releasing cytokines that control other types of leukocytes. Additionally, T cells can differentiate into different subtypes and memory T cells provide antigen-specific immunity to viruses.