What is the answer, and please make it fast.

Which orbitals form a pi bond? a.the s orbital and three p orbitals b.the s orbital and two p orbitals c.overlapping p orbitals d.overlapping hybrid orbitals

An engineer decides to use a slightly weaker material rather than a stronger material, since she knows that the stronger material can break suddenly. this is an example of what? a choosing a material that will show warning before it fails b using composite materials that combine strength c using a material for multiple applications d using design techniques that increase efficiency and reduce cost

Is the genie in the bottle experiment a physical or chemical change/reaction?