What are three physical properties of helium

Which would not reduce the amount of green house gasses in the air

Six solutions are made, each with a y concentration of 1.0 μm and varying concentrations of ab as shown below. based on the concentrations, rank the solutions in decreasing order of reaction rate.

When applying kirchhoff's rules, one of the essential steps is to mark each resistor with plus and minus signs to label how the electric potential changes from one end of the resistor to the other. the circuit in the drawing contains four resistors, each marked with the associated plus and minus signs. however, one resistor is marked incorrectly. which one is it?