Final answer:
In the field of hematology, when examining a blood smear, one should record the color and size, as well as the shape and arrangement of the blood cells, which includes red and white blood cells and platelets, after staining and observing them under a microscope. The correct option is a) Color and size.
Step-by-step explanation:
In the field of hematology, a sub-discipline of biology, when examining a blood smear, it is important to record the general appearance of the blood cells. This includes noting the color and size of the various cell types—red blood cells, white blood cells, and platelets—as well as their shape and arrangement. After the smear is treated with stains, such as the Wright-Giemsa stain, red blood cells should appear pinkish-red, while white blood cells should have various shades of purple nuclei and cytoplasm.
The observation process is usually done using a light microscope with an oil immersion objective lens. It is crucial to evaluate the appearance of red blood cells and platelets first before moving on to a more detailed analysis of the white blood cell population and checking for any potential pathogens.