Question 706Navigation General

The correct answer is D) wind vane. A wind vane is an instrument that indicates the direction of the wind. It is a common navigational tool used on ships, including those operated by the US Coast Guard. The wind vane is designed to rotate and point in the direction the wind is blowing, providing the user with information about the prevailing wind direction. The other answer choices are incorrect because they measure different environmental factors: A) sling psychrometer measures air temperature and humidity, B) hydrometer measures the density of liquids, and C) hygrometer measures humidity levels, but none of these instruments are used to determine wind direction.