Read the passage from When Birds Get Flu and Cows Go Mad! by John DiConsiglio.

Japan, for example, tests a sample from every cow that will be used for food. The meat is kept in refrigerators until the test comes back negative. Most European nations test about 70 percent of their cows.

But in the U. S., only about 650,000 of the 35 million cattle slaughtered each year are tested.

The author most likely includes a signal word so that the reader will recognize

that the passage’s tone is being defined.
that the passage’s cause is being defined.
that there is still a problem.
that the situation is resolved.