When the U. S. government determined the prices of solar panels imported from China were artificially low due to illegal subsidies, it imposed a to help domestic firms compete.

tariff

Explanation:

Government mostly imposed import tax called tariff in economic terms. Tariff is tax which imposed on goods and services that countries import from other country. Tariff imposed to make imports expensive and less desirable,  and to save domestic market by making foreign market less competitive. In this US imposed tariff on china to make its price higher and less competitive in US market.

hygrometers and hair thermometers (often found as part of hygrometers/psychrometers) can be used to measure humidity. barometers are used to measure atmospheric pressure, while anemometers are used to measure wind speed. so the 2nd and 4th choices should be the correct answers.