Click the row number on the left side of the worksheet
Drag across multiple row numbers to select multiple whole rows
Click the first row number, then hold Shift and click the last row number to select a range of rows
Hold Ctrl and click individual row numbers to select non-adjacent whole rows
Press Shift + Space to select the entire active row
Use Ctrl + A to select the entire worksheet, then adjust selection if needed
Click any cell in a row, then press Shift + Space to select that whole row