01 / 6TED-Ed≈ approximate level B24:19–4:25 , .
02 / 6Saturday Night Live≈ approximate level C12:01–2:04
-"Five ," .
03 / 6CrashCourse≈ approximate level B26:39–6:45
, , .
04 / 6SciShow≈ approximate level C18:37–8:43
, , , , .
05 / 6CrashCourse≈ approximate level C16:47–6:52
, , .
06 / 6SciShow≈ approximate level C18:20–8:37
, ’s , , , , , , , .