A capillary is hollow. It is the smallest of the blood vessels, the tubes that carry blood.
cell wall
microtubule
The description of microtubules is hollow rods or hollow cylindrical structures. They mainly help to shape and support the cell.
microtubules
microtubules
The white blood cell has nucleus that red blood cell does not
Microtubules consists of hollow tubes which provide support of the cell.
A microtubule is the structure that supports and shapes the cell.
The microtubule is the mechanism that supports the cell and gives it its shape.
and a red blood cell or in a red blood cell? if its in a red blood cell i would say haemoglobin
Xylem are just made up from cell walls left from cells, making hollow tubes. The walls of these tubes are hydrophilic, so water attaches readily to them, helping it to climb on its way up the plant.