ACROSS 1 lincoln 5 science 9 zero 10 situations 12 passengers 13 idle 14 dodo 15 gallantry 18 schooling 20 ours 23 goat 25 paintbrush 26 appalachia 27 iris 28 erudite 29 synergy DOWN 2 icelandic 3 crossed 4 losing 6 coarsely 7 edition 8 canal 11 the main dish 16 resisting 17 elephant 19 outward 21 ukraine 22 steady 24 on par