Which blood cells fight infection?

**The reasoning** Your body has a defense system against germs, bacteria, and viruses — that's your **immune system**. White blood cells (also called leukocytes) are the soldiers of this system. When infection invades, white cells identify the foreign invaders and destroy them through various mechanisms: some swallow germs (phagocytosis), others produce antibodies that mark invaders for destruction. Think of them as your body's security team, always patrolling for threats. **Why the wrong options tempt you** - **Red cells** carry oxygen throughout your body — that's their job, not fighting infection - **Platelets** help blood clot when you're injured, stopping bleeding — nothing to do with germs - **Plasma** is the liquid part of blood that carries cells and nutrients — it's the transport medium, not a fighter The trap? All these components are *in* your blood, so students guess randomly without thinking about each one's specific function. **Quick takeaway** **White = fight!** Remember: White blood cells are your body's warriors — their whole purpose is defending you against infections.