There are no errors in this sentence. It is a basic simple sentence. Note that the word "mythology" is not correct because it would imply that there is one universal mythology shared by the many different cultures. Instead "mythologies" is appropriate to refer to the differences between the types of mythology. The correct choice is, "loved to study the mythologies of other cultures."

There are no errors in this sentence. The use of the quotation marks around "good" are appropriate because it indicates a special usage of the word - that being that "good" by this person's standards differs from average standards. No additional punctuation or changes are necessary. The correct choice is, "To be considered "good" by his standards, the product."

This sentence contains no errors. The phrase "After much deliberation" is an example of an introductory phrase, explaining information necessary to the context of the sentence, but outside of the main sentence, grammatically. These types of phrases must be followed by a comma in order to separate them from the rest of the sentence. The correct choice is, "After much deliberation, he decided to buy pink roses for his date."

There are no errors in this sentence. The phrase "According to Ancient Greek Mythology" is an example of an introductory phrase, explaining information necessary to the context of the sentence, but outside of the main sentence, grammatically. These types of phrases must be followed by a comma in order to separate them from the rest of the sentence. The correct choice is, "According to Ancient Greek Mythology, Zeus was the king of the Gods."

This sentence contains no errors. It is a simple sentence, so no punctuation is needed whatsoever. Note that the choice that rewords the sentence is grammatically correct, but it is not the clearest or most precise since it replaces the active voice with the passive voice unnecessarily. The correct choice is, "Learning a new language requires many hours of practice."

There are no errors in this sentence. Having a " 's" after each of the individuals' names is appropriate because it shows individual ownership; Hank and Julie do not own the same pets, but their own pets respectively. The correct choice is, "Hank's and Julie's pets caused much trouble around the neighborhood." All other choices change the meaning of the original sentence. While "their" is a possible substitute for "Hank's and Julie's," it is more ambiguous as it implies that they own the same pets when that is not the case. 

This sentence does not contain any errors. It is a simple sentence and is correct as is. The words "absolutely," "differently," and "seemingly" are adverbs, so they do not need to be separated from the other words (verbs or adjectives) with commas. Punctuation of any sort would be inappropriate and would result in an awkward sentence. The correct choice is, "Cole was absolutely fascinated by the ways some materials would react differently under seemingly similar conditions."

There are no errors in this sentence. The underlined portion is one cohesive clause, so no punctuation is necessary. Specifically, a comma should not come before the "and," since the conjunction is not being used to join two independent clauses. Commas should only appear before a coordinate conjunction when the conjunction joins two independent clauses. The correct choice is, "Some experts believe that countries will engage in physical warfare less in the future and engage in more subversive acts of aggression." 

This sentence does not contain any errors. Commas do not appear before the word because when it joins clauses and no changes are needed in general. A semicolon at the end of this clause is also inappropriate because the following clause is not an independent one. The correct choice is, "Duke preferred to listen to audiobooks in stead of reading because he could do other things while listening to them."

There are no errors in this sentence. The phrase "While many people find abstract art strange and confusing" is an introductory phrase, explaining information necessary to the context of the sentence, but outside of the main sentence, grammatically. These types of phrases must be followed by a comma in order to separate them from the rest of the sentence. No additional punctuation or changes are necessary. The other sentences contain errors in voice, punctuation, and tense shift. The correct choice is, "While many people find abstract art strange and confusing, Leah finds most abstract art to be calming."