Multiple choice general knowledge science & technology Which element in the blood helps the body fight against diseases and infections? Red Blood Cells Platelets White Blood cells None of the above Reveal answer Fill a bubble to check yourself C Correct answer Explanation White blood cells (leukocytes) are the immune system's primary defense against infections and foreign invaders. RBCs carry oxygen, platelets help with clotting, and 'none of the above' is incorrect since WBCs do fight disease.