A semicolon is used to separate two independent clauses (independent clauses are two thoughts that could each be their own sentence).  You cannot simply use a comma to perform this task, so “team, her” is incorrect.  If you use a period you must capitalize the next word, so “team. her” is incorrect. And without any punctuation the reader cannot easily tell where one thought ends and the next begins, so “team her” leads to a run-on sentence and is incorrect.

 Notice that the main point of this sentence is that “Dev has become an expert at algebra thanks to his teacher.”  When properly punctuated, the sentence uses “who had always disliked math” as an extra modifying phrase to tell us more about Dev, and “Mrs. Robinson” as an extra description of his teacher. Modifiers/descriptions are often set apart by commas to tell the reader that that information is additional - the reader doesn’t really need to know that information so they can omit it if they’re reading quickly, but if they do want to read it it will help them even-better understand the sentence.

When a sentence features a list, the items in the list should be separated by commas so that the reader can pause between items and so that it is clear which items are in the list. Here there are three items in the list: swim a mile, bike 50 miles, and then run 10 miles. So those items should have commas between them. Note that if you were to use commas around the number of miles, it treats the distance as separate items in the list, and that is not correct.  It is also important here to separate the phrase “while competing in a triathlon” as a modifying phrase describing when these actions took place for Ian. The comma after “triathlon” and before “Ian” lets the reader know that the first few words of the sentence are a descriptive phrase.

 Whenever you see two nouns (or noun phases) directly next to each other, like “Kaitlyn” and “a star gymnast,” there’s a good chance that one of them is being used to describe the other (called an appositive modifier).  This type of modifier should be separated by a comma so that the reader can tell the roles of each noun.  Here that means that “a star gymnast,” a description to tell us more about Kaitlyn, should be separated by commas. Another important use of commas is to (along with coordinating conjunctions like “but” or “and”) separate independent clauses, which we have here.  Two sentences could stand alone: “Kaitlyn made the national team as a sophomore” and “she decided not to join until the summer,” so separating them with a comma plus the coordinating conjunction “but” makes it clear to the reader that there are two separate but related clauses.

When a sentence features two independent clauses - two phrases that could each stand alone as complete sentences with a subject and verb - the two most common and correct ways to separate them are:

1. With a comma plus a coordinating conjunction (such as “or,” “and,” or “but”)

2. With a semicolon

You cannot, however, simply put a comma between them without a coordinating conjunction. Therefore, the sentence that includes the comma but not a conjunction is the improperly crafted sentence.

Answer: NO CHANGE  When a sentence features a list, the items should be separated by commas to help the reader keep the items organized.  This means that the list should read “a scavenger hunt, a three-legged race, and a sleepover”  It is also important to note that with colons and dashes, when they set up a list they need to be used at the end of a complete clause. Here “Emiliy’s birthday party included” is not a complete clause, so you cannot use a colon or dash after “included” to set up the list.  You could, however, use a colon or dash after “Emily’s birthday party included three exciting elements,” for example, as that would be a complete clause.

Answer: “Jupiter, the largest planet in our solar system, weighs”  When two nouns are next to each other, like “Jupiter” and “the largest planet in our solar system” here, there is a good chance that one is being used to describe the other (called an appositive modifier). When that is the case, the modifier needs to be set apart by commas so that the reader can tell that it is a description.  Therefore we need “Jupiter, the largest planet in our solar system, weighs…” so that we know that “the largest planet…” is a phrase describing Jupiter.  Note that “Jupiter is the largest planet in our solar system, it weighs” commits a comma splice error: you cannot separate two independent clauses (complete thoughts that could be their own sentences) simply with a comma - you would need to have a coordinating conjunction such as “and” to go along with the comma.

An ellipsis ( . . . ) is a series of three periods with a space before and after each one. It can be used to show where words in a quotation have been omitted.

When using an ellipsis, make sure that the resulting text is grammatically correct and maintains the same meaning as the original.

The correct answer is "Jennifer . . . decided to accept a job offer from a company that is located in her hometown." because it is grammatically correct and maintains the same meaning as the original text. 

"Jennifer . . . take a job offer from a company that is located in her hometown." is not grammatically correct because of a shift in verb tense. "Take" is in the present tense, but the original text is in past tense. 

"Jennifer . . . is located in her hometown."  does not maintain the same meaning as the original text. 

""Jennifer applied to jobs all over the country . . . located in her hometown."" does not maintain the same meaning as the original text. 

An ellipsis ( . . . ) is a series of three periods with a space before and after each one. It can be used to show where words in a quotation have been omitted.

When using an ellipsis, make sure that the resulting text is grammatically correct and maintains the same meaning as the original.

The correct answer is "Two phytochemicals in ginger . . . are seen as helpful for reducing nausea and improving digestion." because it is grammatically correct and maintains the same meaning as the original statement. 

""Two phytochemicals . . . are seen as helpful for reducing nausea and improving digestion."" is not correct because it doesn't main the same meaning as the original statement. 

"Two phytochemicals in ginger . . . are seen as helpful for reduce nausea and improving digestion." is not correct because it is not grammatically correct. There is an incorrect verb tense shift. "Reduce" is in the incorrect verb tense. 

An ellipsis ( . . . ) is a series of three periods with a space before and after each one. It can be used to show where words in a quotation have been omitted.

When using an ellipsis, make sure that the resulting text is grammatically correct and maintains the same meaning as the original.

"The local farmer's market . . .  is only open on Fridays and Saturdays." is the correct answer because it is grammatically correct and maintains the same meaning as the original statement. 

"The local . . . is only open on Fridays and Saturdays." is not correct because it does not maintain the same meaning as the original statement. 

""The local farmer's market . . . open on Fridays and Saturdays."" is not correct because it is not grammatically correct. 

""The . . . where individuals sell their own goods and produce, is only open on Fridays and Saturdays."" is not correct because it is not grammatically correct and does not maintain the same meaning as the original text.