Tasks priorities and RAM

Hello, in the FreeRTOS Using Guide there is written that more Tasks priorities will consume more RAM. But why is that so? Thanks!

Tasks priorities and RAM

Read tasks are referenced from an array of linked lists, with an array position for each task priority. For example, priority 0 tasks are referenced from the list in array index 0, priority 1 tasks from the list in array index 1, etc. The more task priorities the larger the array.