Guide. A bone density test measures the density of minerals (such as calcium) in your bones using a special X-ray. This information is used to estimate the strength of your bones.
Animal cells do have vacuoles, but they are smaller, larger in number (plant cells usually have just one or a few large vacuoles) AND serve a somewhat different purpose than those of plants.
Vacuoles are mostly composed of water and amino acids with a membrane made of phospholipids. In plants, vacuoles are much larger than in animal cells and are in a central location. In animal cells, the vacuoles can be anywhere in the cell's cytoplasm except in the nucleus or cell membrane. In fact, vacuoles move around in the cell in order to dispose of any waste they hold.