Learn Turkish: Hepsi zararlı plastik yerine doğal ahşap oyuncak üretir. - All of them produce natural wooden toys instead of harmful plastic.

Yerine means instead of or in place of. It comes directly after the thing being replaced. In this sentence, it comes right after zararlı plastik, meaning instead of harmful plastic. Because we are talking about a general material, plastik does not need any special case endings before yerine.

The translation says toys, but the Turkish word is singular (oyuncak). Why is it not oyuncaklar?

In Turkish, when you talk about general categories or things produced in mass as a direct object, you usually leave the noun singular. Because they produce toys as a general concept, oyuncak is used instead of the plural oyuncaklar.

Why does hepsi take the singular verb üretir instead of the plural üretirler?

Even though hepsi means all of them and refers to a group, words like this take a grammatically singular verb in Turkish. Therefore, the verb takes the third-person singular aorist ending -ir, making it üretir.

Why does the instead of part come before the natural wooden toys part?

Turkish word order often places extra details before the main direct object. Here, zararlı plastik yerine describes the circumstances of what they produce, so it naturally comes before the object doğal ahşap oyuncak and the verb at the very end.