Topic 1: Increasing travels between countries enable people to learn different cultures or to increase tension between people from different countries

 
49.
 
Essential 
+ 
characteristic, component, element, feature, part, point, role, service, tool
 
50.
 
Ethical 
+ 
code,  concern,  consideration,  dilemma,  implication,  issue,  lapse, 
principle, problem, question, reason, standard, value
 
51.
 
Ethnic 
+ 
background,  community,  conflict,  difference,  diversity,  division,  group, 
identity, minority, origin, tension, violence
 
52.
 
Experienced  + 
people, player, practitioner, professional, staff, teacher, worker, user
 
53.
 
Extensive 
+ 
collection,  coverage,  damage,  discussion,  experience,  knowledge, 
research, review, study, survey, use
 
54.
 
External 
+ 
affair,  agency,  appearance,  constraint,  environment,  factor,  force, 
influence, pressure, reality, source, stimulus, threat, use, world 
55.