A boy sets up a picnic on the beach next to a sand dune. How are sand dunes formed? A. erosion and deposition
B. weathering and erosion
C. tectonic plates
D. precipitation​

Transportation is the largest single source of air pollution in the united states. air pollution can harm the environment and human health. which technology could offer a solution to this problem? mufflers that reduce noise motors that run on electricity tires that improve gas mileage

Ageochemist examines a piece of metal that he found in the soil. he performs tests to identify the metal from its density, electrical conductivity, and melting point. which statement best describes his investigation? a. he is determining physical properties that are sufficient to identify the metal.b. he is determining chemical properties that are sufficient to identify the metal.c. he is determining physical properties that are insufficient to identify the metal.d. he is determining chemical properties that are insufficient to identify the metal.

What is the molarity of the solution produced when 145 g of nacl is dissolved in sufficient water to prepare 2.75 l of solution?