What laboratory tool is typically used to draw liquids into a pipette?

The pipette bulb is specifically designed for drawing liquids into a pipette by creating a vacuum when squeezed and released. This tool allows for precise control over the amount of liquid being drawn into the pipette, facilitating accurate measurements essential in laboratory work. It ensures that the liquid is drawn up smoothly and without contamination, making it crucial for handling various solutions in experiments.

In contrast, the other tools mentioned do not serve this purpose. A mortar and pestle are used for grinding and mixing substances, forceps are employed for grasping or holding small objects, and a funnel is designed to help pour liquids into containers with a narrow opening. Therefore, the pipette bulb is the appropriate tool to use when needing to fill a pipette with liquid.