Question

what function is the bolded word or phrase serving in the sentence?
marik ishtar practiced balancing on a tightrope for months before performing in the circus.
modifier
object
subject

Explanation:

The bolded phrase "balancing on a tightrope" is the object of the verb "practiced" in the sentence. The subject is "Marik Ishtar", the verb is "practiced", and the object receives the action of the verb, which here is the activity "balancing on a tightrope".

Answer:

Object