Find the non permissible replacement for a in the expression of 4/-9a?

Select the correct answer from each drop-down menu proteins are

Which skeletal system is represented by the shaded portion of the skeleton? spongy skeleton compact skeleton axial skeleton appendicular skeleton

The data below simulate what happened to peppered moths in england after the industrial revolution which statement best describes the process that produced one of the emding populations of moths ?light colored moths were selected for on light colored trees