What makes the atomic radius change along a period in the periodic table

If the root word engage means “to connect with something,” what does the word disengage mean in the following sentence? he disengaged the gears by stepping on the clutch pedal. a.added more engine powerb. activated a connection to the pedalc. stalled the engined. released a connection to the pedal

The identities of substances are the same before and after which type of change

At element makes up all organic compounds?