Final answer:
In the CSS rule provided by the student, .error_text is the selector, which targets all elements with the class 'error_text' to apply the specified styles.In CSS, the selector ".error_text" targets elements with the corresponding class, applying the specified styles, such as red text color.
Step-by-step explanation:
The student asked about a specific CSS rule, wanting to know which part is considered the selector. In the provided rule .error_text { color: red; }, the selector is .error_text. The selector in CSS is used to target HTML elements that will be affected by the defined styles within the curly braces {}. In this case, .error_text is a class selector, which means that it selects all elements with the class error_text and applies the specified styles to them, making their text color red.
Understanding CSS rules is integral to effective styling in web development. In the given rule .error_text { color: red; }, ".error_text" is identified as the selector. In CSS, selectors pinpoint the HTML elements subject to the styles defined within curly braces {}. In this instance, ".error_text" represents a class selector, signifying its application to all elements adorned with the "error_text" class. Consequently, any HTML element carrying this class designation will have its text color set to red, exemplifying how selectors, such as class selectors, play a pivotal role in tailoring styles to specific elements and facilitating the cohesive presentation of web content.