Explain the difference between serif and sans-serif fonts.

The main difference between serif and sans-serif fonts lies in the presence or absence of small decorative lines, known as serifs, at the ends of the strokes of the characters.

1. **Serif Fonts**:
   - Serif fonts have small decorative strokes, or serifs, at the ends of the main strokes of characters. These serifs can be described as small lines, curves, or embellishments that extend from the main strokes.
   - Serif fonts are often associated with tradition, formality, and readability in printed materials such as books, newspapers, and magazines. The serifs help guide the eye along the text and create a sense of flow and continuity.
   - Common examples of serif fonts include Times New Roman, Georgia, Garamond, and Baskerville.

2. **Sans-serif Fonts**:
   - Sans-serif fonts, as the name suggests, do not have serifs. They feature clean, simple lines without any decorative embellishments at the ends of the characters' strokes.
   - Sans-serif fonts are often perceived as modern, clean, and straightforward. They are commonly used for digital screens, such as websites, mobile apps, and user interfaces, due to their legibility and simplicity.
   - Sans-serif fonts are also preferred for body text on screens, as they tend to display well at smaller sizes and on low-resolution displays.
   - Common examples of sans-serif fonts include Arial, Helvetica, Roboto, and Calibri.

In summary, the primary difference between serif and sans-serif fonts is the presence or absence of serifs. Serif fonts are characterized by decorative strokes at the ends of characters and are often associated with tradition and readability in print. Sans-serif fonts, on the other hand, have clean lines without serifs and are commonly used for digital screens due to their modern, legible appearance. Both types of fonts have their own strengths and are suitable for different design contexts and applications.