Final answer:
The correct action for preparing a blood smear is to place a 1 mm drop of blood about a half-inch from the edge of the slide to ensure the creation of a smear with a feathered edge for microscopic analysis of individual cells.
Step-by-step explanation:
When preparing a peripheral blood smear, the appropriate action is to place a 1 mm drop of blood about a half-inch from the edge of the slide. This technique allows for the creation of a blood smear with a feathered edge when the smear is made using a spreader slide. The feathered edge is essential for viewing individual cells under a microscope because it produces a single layer of cells which can be analyzed more accurately.