A ladder, ramp, or stair is required for any grade separation where the _______________ changes by _____ inches or more. Group of answer choices Elevation; 24 inches Elevation; 19 inches Height; 18 inches Height; 16 inchesWhen leaning an extension ladder against a landing for access and egress, the ladder must extend at least _______ inches above the landing and be_____________________. Group of answer choices 24 inches; secured 19 inches; held by another employee 36 inches; secured 48 inches; secured at top only