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.
So, at the moment, Pluto is the furthest of the planets from the Sun. Its distance is just over 39.5 AU. (An AU, or astronomical unit, is the mean distance of the Earth from the Sun, which is approximately 150 million kilometres). The possibility of there being another planet, the so-called Planet X, has been suggested.