The most basic data objects that can be added to a Multiple Variables graph are individual Symbols. Each symbol on the graph will represent a single row in the data table, and customization options for these data objects include:
•Size
The option to enable - or disable - symbols being plotted on the graph can be controlled by a Show Symbols checkbox at the top of the page (on Mac, this is a toggle as opposed to a checkbox). This control is shared across all of the Symbol option tabs (in other words, if you uncheck Show Symbols on the Fill and Border tab, it will also be unchecked on the Size and Labels tabs).