What is the object pronoun in green palm trees were growing desert?

There is no object pronoun in the sentence "Green palm trees were growing in the desert."

Here's why:

* Pronoun: A pronoun replaces a noun. Examples include "he," "she," "it," "they," "them," "me," "you."

* Object Pronoun: An object pronoun is used as the object of a verb or preposition.

* Subject: In the sentence, "Green palm trees" is the subject, performing the action of growing.

* Preposition: "In" is a preposition.

* Object of Preposition: "The desert" is the object of the preposition "in."

Since there's no pronoun used as the object of the verb or preposition, there's no object pronoun in this sentence.