Letters that make background level
a, o, b, d, e, g, k, l, n, c, r, u, v are letters that make 'background level'
Words within background level
el, ground, ground level, BA, UN, Ba, AC, lev, Ro, kg, EL, level, Eve, eve, round, back, background, eV, ND, LE, Ac, Nd are words within 'background level'