Answer:
microvilli
Explanation:
having microscopic projections called microvilli. The epithelial cells of the proximal convoluted tubule are adapted.
The nucleus will have the greatest mass. Among the 3 kinds of subatomic particles, electrons are the lightest (by several orders of magnitude), protons and neutrons are much closer is magnitude, though neutrons are slightly heavier. However, in the diagram, the nucleus contains both the neutrons and the protons, so its combined mass would be heavier than either the neutrons alone or the protons alone.
