Find the relative (adjective) clause in the sentence. Then find the two locations where commas are needed. The passengers who were all wearing their seatbelts were not injured in the car crash.

themselves

an intensive pronoun is a pronoun that ends in self or selves, such as himself, herself, themselves, yourself, ourselves. since band members is a third person plural, the correct intensive pronoun would be themselves. if the band was talked about as a collective noun, itself would be the appropriate intensive pronoun. intensive pronouns are used to add emphasis to the noun it's modifying which is why it directly follows it.

ian mortimer in his book "the time traveller's guide to elizabethan england" uses a narrative in his style, which successfully conveys a clear description of the life in england in the 16th century. he writes in second person, which makes it comfortable to reader and easy to understand, he captures the readers attention with views of the landscape, the streets, the people including rich and poor. he also depicts some cultural traits from how people behave, eat or what they wear. his descriptions range from the social, economical, the political power to the examples of the life of common people. it could be tell that this book is about social history rather than a   novel.