Final answer:
In English, parentheses are commonly used to insert extra, optional information or clarification into a sentence. The word 'traits' could be in parentheses in Sentence 1 to provide additional context or a clarification.
Step-by-step explanation:
In the English language, parentheses are used to enclose information that is not essential to the main point of the sentence but provides additional context or clarification. If the word 'traits' is placed in parentheses in Sentence 1, it could be that the author of the sentence is providing extra, non-essential information about something. Another possibility is that the author is clarifying what they mean by a previous statement. Without the specific sentence, it's challenging to give a precise answer. However, these are the most common reasons why a word would be placed in parentheses.
Learn more about use of parentheses