Make a 24 pixel wide by 12 pixel high ellipse. Next choose the rounded rectangle tool from the toolbox and click the artboard once to open the options. Set the width to 15 pixels, the height to 100 pixels, and the corner radius to 12. Position the two pieces as shown on the left below. Use the Align palette to align the horizontal centers.
Select only the top ellipse. Hold the opt/alt key and start to drag downward, then press and hold the shift key while you drag in a straight line downward to add another ellipse to the bottom of the stem. Holding the opt/alt key as you drag makes a copy; holding shift constrains the drag to a straight line.