回答
- It would be difficult to tell (the nationality) if only one person is there, but it would be easy if two or more people are there as features become prominent.
◆「1人だと難しいが」・"It would be difficult to tell the nationality if only one person is there,"（1人しかそこにいない場合は国籍を当てるのは難しいだろう）◆「2人以上なら簡単」・"it would be easy if two or more people there"（2人またはそれ以上そこにいるなら簡単だろう）◆「特徴が滲み出て」は・"as features become prominent" （特徴が顕著になるので）と解釈しました。上記の例文でおっしゃりたいニュアンスが出ていれば幸いです。
日本 
