"Under the teacher's guidance" is an introductory phrase, one that conditions the action of the sentence, but is apart from its main structure. Any introductory phrase needs to be set apart fom the main body of the sentence by a comma. The only answer choice that correctly uses a comma to separate the phrase is "Under the teacher's guidance, the students' reading ability improved."

"Unlike his family" is an introductory phrase, one that conditions the action of the sentence, but remains apart from its main body. Any introductory phrase must be set apart from the rest of the sentence by a comma. The only answer choice that correctly uses the comma is "Unlike his family, the man became deeply religious as he got older."

"Just like his father" is an introductory phrase, one that conditions the action of the sentence, but remains outside its main structure. Any introductory phrase must be set apart from the body of the sentence by a comma. The only answer choice that appropriately uses a comma in this way is "Just like his father, the little boy had flaming red hair."

"For the new model" is an introductory phrase, one that conditions the action of the sentence, but remains outside of its main structure. Any introductory phrase must be set apart from the rest of the sentence by a comma. The only answer choice which properly uses the comma is "For the new model, everything about the car was changed."

The phrase "For the new team" is an introductory phrase, one that conditions the meaning of the sentence but remains outside its main structure. All introductory phrases need to be set apart from the sentence by a comma. The only answer choice to correctly do this is "For the new team, the coach intentionally sought out different kinds of players."

It may take you a moment to figure out that "the raccoon" is not actually the subject of the sentence and "this mammal" is since the nouns appear right next to each other. The phrase "Unlike its distant cousin the raccoon" is an introductory phrase, giving a condition in which to understand the main body of the sentence. All introductory phrases need to be set apart from the rest of the sentence by a comma. Therefore, the correct answer choice is "Unlike its distant cousin the raccoon, this mammal."

The sentence, as written, actually contains two separate phrases, with "When reaching for metaphors" being an introductory phrase. Introductory phrases always need to be set off by commas; therefore, the correct answer is "When reaching for a metaphor, authors often make their point more confusing."

The phrase "the first in the county in years" is an interrupting phrase, a clause that provides information to the sentence but is not crucial to the structure. All interrupting phrases need to be set apart from the rest of the sentence by commas; therefore, the correct answer choice is "The exciting political race, the first in the county in years, drew."

The phrase "In the first heat" is an introductory phrase in the sentence, one that conditions the meaning of the sentence (or in this case, the first part of this compound sentence), but remains apart from its structure. All introductory phrases need to be separated from the rest of the sentence by a comma. As this is the only punctuation error in the sentence as written, the correct answer choice is "In the first heat, every car spun out, and none of the racers finished the required four laps."

The phrase "for three years" is an introductory phrase, one that conditions the meaning of the sentence but is not part of the necessary structure of the sentence. All introductory phrases should be set off by a comma from the rest of the sentence. Therefore, the correct answer choice is "For three years, the fugitive lived."