Answer: "if"
Explanation:
Signal words are referred to as the words that provide hints on what is expected to happen while one is reading.
The signal word that points to the problem in the passage is "if". From the text, we can see that Hughes knew that the meat that comes from a single cow could not make many people sick buy that the real danger was "if" the disease was passed to other cows.
Answer:
Explanation: American literature in the early twentieth century reflected changes in the way he wanted to translate his writings giving them a more social sense and deepening more in the lives of rich and poor. And shaping what was experienced in the Industrial Revolution and the hardships lived after the war. This change accommodated the innovation in terms of arguments. Police novels had a great boom, just like black novels where social criticism was felt.