For each problem, define whether you are calculating for a scalar or vector quantity. Show your work to receive full credit. A skateboarder travels 200 m in 3,380 secs. What is the speed of the skateboarder?

Embryos of different species look very similar, which shows that the organisms share a ancestor.

Ahypothrticalax type of ceramic material is known to have a density of 2.10 g/cm3 and a unit cell of cubic symmetry with a cell edge length of 0.57 nm. the atomic weights of the a and x elements are 28.5and 30.0 g/mol, respectively. on the basis of this information, which of the following crystal structures is (are) possible for this material: sodium chloride, cesium chloride, or zinc blende

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.