Letters that make internal control
a, o, e, l, n, c, r, t, i are letters that make 'internal control'
Words within internal control
ER, te, NT, intern, RN, inter, Ro, internal, on, con, in, control, ern, tern, AL, CO, IN, Al, Co, Er, In, Rn, Na, Te, RNA are words within 'internal control'