Identify the antecedent for the underlined pronoun in each sentence below:
Albo
The car has a leak in its transmission
More and more physicians are beginning to look not just for illnesses but also for patients' habits with long-term health
implications. This is definite progress.
The cow twitched its tail at the fly.
Someone from the circus led the injured horse out of the ring.
The rain continued to fall, and the mud grew deeper until it finally stopped.

The antecedent of a pronoun is the word or phrase whose place the pronoun takes. In some cases, the antecedent is obvious, while in others it's either missing or not clear.

In the first and third sentences, it's simple. In the first sentence, a car's transmission is mentioned. Instead of repeating the word car, we will use the pronoun it and its possessive form its. It's the same in the third sentence (cow's tail - its tail).

The second example is interesting because the antecedent of the pronoun this is the entire previous sentence.

In the fourth sentence, the antecedent is missing. We don't know instead of what word the pronoun someone is used.

In the fifth, the antecedent is not clear as the pronoun it could be used to refer to the word rain, or the word mud.