Question

what temperature pattern do the isotherms show?
temperatures increase from south to north.
there is a zone of low temperatures in the southwest.
there is a zone of high temperatures in the center of the country.
temperatures increase from the center of the country toward the southeast.

Explanation:

1. Analyze option 1: Isotherms (temperature lines) show higher values in the south (90 in Florida) and lower in the north (20 in the northern plains), so temperatures decrease from south to north. This option is incorrect.
2. Analyze option 2: The Southwest has isotherms of 40-50, while the central northern U.S. has 20-30, so the Southwest is not a low-temperature zone. This option is incorrect.
3. Analyze option 3: The center of the country has isotherms of 20-40, which are lower than the Southeast's 70-90, so it is not a high-temperature zone. This option is incorrect.
4. Analyze option 4: The central U.S. has lower temperatures (20-40) that rise steadily to 70-90 as you move toward the Southeast (Florida, Gulf Coast). This matches the isotherm pattern.

Answer:

Temperatures increase from the center of the country toward the Southeast.