Oral route. Many drugs can be administered orally as liquids, capsules, tablets, or chewable tablets. Because the oral route is the most convenient and usually the safest and least expensive, it is the one most often used. However, it has limitations because of the way a drug typically moves through the digestive tract.
Measuring Distances to Stars. Astronomers use several techniques for discovering how far away an object is. The first is called trigonometric parallax and is based on geometry, but it is only good for up to about 500 light-years.
This is a diagram that zooms out from the Earth's orbit to the nearest star system. It tries to show just how large the distance to the nearest star really is. Here is a map of all the known stars that lie within 20 light years plotted using the data provided below. Data and Catalogs. There are over 100 stars within 20 light years. This is a list of the known stars that lie within this distance.