China has the world's highest population but its large land area makes its population density low, doesn't it?
人口＝population
国土（面積）＝land area
人口密度＝population density
China is the most populated country in the world-などとされてもいいと思います。
its large land area makes its population density low, doesn't it?＝その大きい国土が人口密度を低くしていますよね？ としてみました。
China has the highest population in the world but her population density is not very high because her land is also huge.
Population density : 人口密度
例
Tokyo is densely populated.
東京は人口密度が高い。
国
Land, area of land, territory(領土)
The land of China is also huge.
中国の国土もすごく大きい。
訳
中国は人口は世界で一番だが、国土も巨大なために人口密度は小さい。
日本 
