$2.$USA Airlines uses the following performance measures. Classify each performance measure into the most likely balanced scorecard perspective it relates to: customer, internal process, innovation and learning, or financial.

$\backslash$table$[[$Performance measure$],[1.$ Cost of leasing airport gates,$],[2.$ Gallons of oil used,$],[3.$ Cost of leasing airplanes,$],[4.$ Employee diversity training sessions completed,$],[5.$ Time airplane is on ground between flights,$],[6.$ Percentage of waste recycled,$],[7.$ Cash flow from operations,$],[8.$ Airplane miles per gallon of fuel,$],[9.$ Safety violations per mile flown,$],[10.$ Percentage of ground crew trained,$],[11.$ Return on investment,$]]$