In HTML table design, how can you create a table where different rows have different numbers of visible cells or columns?

Introduction / Context:
Web developers often need to create HTML tables where some rows span multiple columns or have fewer visible cells than others. For example, a header row might span all columns, while data rows have more detailed cells. This question asks how you can have a different number of cells in each row of a table. It tests your understanding of the HTML table model, including the use of <tr>, <td>, <th>, and the colspan attribute for column spanning.

Given Data / Assumptions:

• You are creating a table using HTML <table>, <tr>, <td>, and <th> elements.
• Some rows should have many detailed cells, while other rows should have fewer cells spanning multiple columns.
• You want the layout to render correctly in standard web browsers.
• The table can have an irregular visual structure, but the markup must still be valid and readable.
• You may use attributes such as colspan for cell spanning.

Concept / Approach:
The HTML table model groups cells into rows using <tr>. Within each row, you can place header cells (<th>) or data cells (<td>). Browsers do not require every row to have exactly the same number of cell elements. Instead, you can use the colspan attribute on a cell to span multiple columns and effectively reduce the number of cell tags in that row. For instance, a single <td colspan="3"> cell can cover the space of three regular cells. By combining different counts of <td> and <th> elements and colspan values, you can create rows with different numbers of visible cells while keeping the table structurally sound.

Step-by-Step Solution:
Step 1: Define your table layout and decide which rows need multiple detailed columns and which rows should span columns. Step 2: For each row, create a <tr> element. Inside that row, add as many <td> or <th> elements as required for your design. Step 3: When a cell should cover more than one column, give that cell a colspan attribute, for example <td colspan="3"> to span three columns. Step 4: In other rows that should show each column separately, simply include individual cells without colspan so each column is represented explicitly. Step 5: Test the table in a browser to ensure the visual layout matches your intended design, adjusting colspan values or the number of cells per row as needed.

Verification / Alternative check:
You can verify this behavior by building a small example. Create a table with three columns in the first data row using three <td> cells. In the second row, use a single <td colspan="3"> cell. Browsers will render the first row as three separate columns and the second row as one cell spanning the full width where those three columns would be. This confirms that different rows can have different numbers of cell tags as long as column spanning is used appropriately.

Why Other Options Are Wrong:
Option B is wrong because no DOCTYPE forces identical cell counts in every row; HTML focuses on logical structure and browsers handle irregularities. Option C suggests creating a separate table per row, which complicates layout and semantics and is unnecessary. Option D is irrelevant, since databases store data, not visual HTML layout rules. Option E is misleading, because disabling validation does not magically create correct layouts; proper markup with <td>, <th>, and colspan is the real solution.

Common Pitfalls:
A common pitfall is forgetting that colspan values must align logically with the rest of the table. If you mix inconsistent colspan values across rows, the layout can become confusing or misaligned. Another issue is using many nested tables instead of a single table with appropriate spanning, which can make HTML harder to maintain. Understanding that different rows can legitimately contain different numbers of cells, and that colspan is the standard way to implement such layouts, leads to cleaner, more maintainable markup.

Final Answer:
You can have different numbers of cells per row by simply placing the required number of &lt;td&gt; or &lt;th&gt; cells in each &lt;tr&gt; and using the colspan attribute so that some cells span multiple columns, giving rows fewer visible cells than others.