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.
In plant cells, vacuoles store water and maintain turgidity of the cell. In animal cells, they store water, ions and waste. Another difference among them is that plant cells have chloroplasts for photosynthesis, which allows them to covert sunlight into food for the cell.