Read the passage from When Birds Get Flu and Cows Go Mad! by John DiConsiglio. Hughes knew that the meat from a single cow couldn’t make very many people sick. The real danger was if the disease was passed to other cows. How could that happen? After cows are slaughtered, the parts you can eat go to meat processing plants to be made into hamburger and steaks. The parts you can’t eat—like the bones and hooves—are often sent to factories that grind them into meal for animal feed. The signal word that points to the problem in the passage is "if." "how." "after." "like."