Answer: Phagocytosis (engulfing and digesting pathogens).
- A Secreting antibodies directly into the bloodstream
- B Phagocytosis (engulfing and digesting pathogens)
- C Releasing antiviral interferon signaling proteins
- D Raising local tissue temperature to kill germs
Correct answer: B. Phagocytosis (engulfing and digesting pathogens)
Explanation: Neutrophils are the most abundant WBCs and are the first to arrive at infection sites. They engulf pathogens by phagocytosis, trapping them in phagosomes that fuse with lysosomes containing digestive enzymes.
An antibody is Y-shaped, with two identical antigen-binding sites at the tips of the variable regions - each shaped to recognise one specific antigen - while the constant (Fc) region at the base is recognised by immune cells to trigger further responses.
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.