The word “they” in the last paragraph refers to to_____________,
A. insoluble ions
B. soluble ions
Sep choose the correct answer before viewing the answer and the solution below.
The QG High School Examination 2021 subject ANH
Correct answer: A
In the article: “Insoluble ions such as aluminum, iron, and silicon stay where they are and form the thin, fertile skin of soil on which vegetation can grow.” (Insoluble ions such as aluminum, iron and Silicon stay where they are and form the thin and fertile soil on which plants can grow)
=> they = Insoluble ions