Why do you think the American government interned a majority of Japanese-Americans and very few German Americans during World War II?

As you think about this question reflect on how the following might have made it easier to target the Japanese American population:

1. Ethnic enclaves 
2. Phenotype
3. Melting Pot v. the  theories of assimilation
4. Settlement Patterns
5. Time-Period of Immigration of U.S.