Answer:
LysThrHis, LysHisThr, HisLysThr, HisThrLys, ThrLysHis, ThrHisLys
Explanation:
You easily combine the options for the tripeptide if you made a chart
Also you can calculate the posibilities with the factorial function in the calculatio (x!): 3*2*1 (you can multiplicate the number of amoniacids by the followed numbers until 1) = 6
