Vocabulary consisting only from characters you are able to read
験
shirushi
(1)mark, (2)symbol, (3)evidence; mix
種々
shuju
variety; varietymix
課題
kadai
subject/theme/task/challenge/issue/matter/(P)jlpt3, leda1
観察
kansatsu
observation, surveysuru
億
oku
(num) 100,000,000, hundred millionjlpt4
戦
ikusa
(1)war, battle, campaign, fight, (2)(arch) troops, forces; (3)war, battle, (4)match, competition mix