Which word in the sentence is used incorrectly: "It's true that children depend in their parents for food, clothing and shelter"?

The word "in" is used incorrectly in the sentence. The correct preposition to express the relationship between children and their parents regarding the support they receive is "on." The phrase should read "depend on their parents" because "depend on" is the standard collocation used in English to indicate reliance or need for support from someone. The other words in the sentence are used correctly in their respective contexts: "It's" is a contraction for "It is," "depend" is the verb that indicates reliance, and "clothing" is a noun that appropriately describes one of the necessities that children receive from their parents. Thus, the use of "on" instead of "in" would ensure that the sentence conveys the intended meaning accurately.