Final answer:
Both platelets and some leukocytes, specifically the granular leukocytes (neutrophils, eosinophils, basophils), share the feature of having granules within the cytoplasm.
Step-by-step explanation:
The feature shared by platelets and some leukocytes is the presence of granules. While platelets are not complete cells and lack a nucleus, they do contain granules that play a key role in blood clotting. Additionally, granular leukocytes, which include neutrophils, eosinophils, and basophils, contain abundant granules within the cytoplasm and have a lobed nucleus. Conversely, agranular leukocytes like lymphocytes and monocytes contain smaller, less-visible granules in their cytoplasm compared to granular leukocytes, and their nucleuses are simple in shape with some indentation but without distinct lobes.