To answer skeptics, Gallup has laid out a more detailed anatomical description of the process in the medical literature.

为了回答怀疑论者，盖洛普在医学文献中对这一过程进行了更详细的解剖学描述。

Because this is a list of actions in a description of the process, the speaker leaves out 'has to be', which applies to all of the steps.

因为这是过程描述中的动作列表，所以演讲者省略了适用于所有步骤的“必须” 。