How can you iterate over a two-dimensional array using nested loops?

You can iterate over a two-dimensional array using nested loops by looping through each row and then each column.

In a two-dimensional array, data is stored in a tabular format, i.e., in rows and columns. To access each element, you need to know its row index and column index. This is where nested loops come in handy. The outer loop iterates over the rows, and the inner loop iterates over the columns of each row.

Let's consider a two-dimensional array, `arr[][]`, with `m` rows and `n` columns. Here's how you can iterate over it using nested loops:

```java
for (int i = 0; i < m; i++) { // Looping over rows
for (int j = 0; j < n; j++) { // Looping over columns
System.out.println(arr[i][j]);
}
}
```

In this example, `i` is the index for rows and `j` is the index for columns. The outer loop `for (int i = 0; i < m; i++)` iterates over each row. For each iteration of the outer loop (i.e., for each row), the inner loop `for (int j = 0; j < n; j++)` runs, iterating over each column in the current row. The statement `System.out.println(arr[i][j]);` then prints the element at the `i`th row and `j`th column.

This method of iteration is known as row-major order, which is the most common method in many programming languages, including Java and Python. However, it's also possible to iterate in column-major order (first by columns, then by rows) by swapping the order of the loops.

Remember, the indices of arrays in most programming languages start from 0, so the loops run from 0 to `m-1` and 0 to `n-1` respectively. Also, the number of iterations of the inner loop depends on the current iteration of the outer loop, hence the term 'nested loops'.