What runs all the way around the house but never moves?

An automobile steering wheel is shown. what is the ideal mechanical advantage? if the ama is 8, what is the efficiency of the steering wheel?

Why does karst topography exist in some geographic location? a. few climates have enough oxygen b. most regions have rock layers other than limestone c. in most regions, the soil is too thin d. the water is too acidic enough in most places

Language is not the only way that humans communicate. describe how we use sound, touch, chemicals, and sight to communicate. need answer asap