Step 1: Defining White Blood Cells.
White blood cells, or Leukocytes, are an essential part of the immune system, helping to fight infections and foreign invaders.
Step 2: Understanding the Role.
Leukocytes play a key role in defending the body against harmful pathogens.
Step 3: Verifying the Options.
Option (1): Erythrocytes are red blood cells, not white.
Option (2): Leukocytes are the correct answer, referring to white blood cells.
Option (3): Thrombocytes are platelets, involved in blood clotting.
Option (4): Lymphocytes are a type of white blood cell but not the general term.