The underlined portion does not show proper subject-verb agreement. Although there are "children" playing, the sentence refers to "each," which is singular. "Each of the children is" is the correct answer.

The original text contains a pronoun agreement error. The possessive pronoun "their" is plural, but it is intended to refer to the singular noun "individual." We must use singular possessive pronouns instead, such as "his or her."

Only answer choices "depends on his or her weight, height, and how old they are" and "depends on his or her weight, height, and age" correctly use "his or her" instead of "their," but answer choice "depends on his or her weight, height, and how old they are" does not use correct parallel structure. Therefore, the answer choice "depends on his or her weight, height, and age" is correct.

The original text contains a pronoun reference error. The antecedent of "its" is "empires," which is plural. We should therefore use the plural possessive pronoun "their" instead of the singular possessive pronoun "its." Only the answer choice "is that they became too large for their governments to collect tax revenues from citizens" correctly uses the plural posessive pronoun.

The original sentence lacks agreement. “Half of the states” is plural and in the third person, so it should say “as their official languages.” 

Since the government is a thing or institution, the sentence should say “its taxpayers.” The contraction “it’s” stands for “it is,” and therefore, is not possessive.

The pronoun "it" should be plural because its antecedent is the plural subject "resources." Only two choices correcty change "it" to "they," but one of them, "as they depend on the reduction of foreign oil," confuses cause and effect. The resources are not dependent on the reduction of foreign oil. The correct answer is "as they may reduce our dependence on foreign oil."

The sentence as written contains one small error. "It," a singular pronoun, is used to refer to the plural "sporting events." In order to fix this issue, the pronoun needs to be made plural, which is done in "Most men who go to sporting events find them an enjoyable diversion."

In this sentence, the subject is "anyone," a singular pronoun. Therefore, all pronouns relating back to "anyone" should be singular. In the underlined portion of the sentence, "preparing a plan that they stick to," "they" is plural, not singular. Now that we have identified the problem, we have to figure out how to correct it.

Given that "anyone" is gender neutral, the best way to improve this sentence is avoid the use of a gendered pronoun (meaning "he" or "she") and simply avoid using a pronoun at all. The correct answer, "preparing a plan and sticking to it," accomplishes this objective and is therefore the best way to improve the sentence.

The original sentence contains an error in noun-pronoun agreement: the plural possessive pronoun "their" is used to refer to "the worker," a singular noun. We need to use a singular possessive pronoun to refer to a singular noun, and our choices in this case are "his," "her," and "its." One doesn't use "its" to refer to people, and while "the worker" is not a gendered noun, we can tell that the worker being described in the sentence is male because of the use of the possessive pronoun "his" in the phrases "his lost green helmet" and "made his way home happily." For the sentence to be correct, we need to replace "their" with "his," so the correct answer is "Just as he finished work for the day, the worker found his lost green helmet and made his way home happily."

Choose a pronoun that properly agrees with the subject. In this case, "basketball team" is singular, although it represents a group of people, and should be accompanied with "its," instead of "their."