You can see this structure in paragraphs whether they are narrating, describing, comparing, contrasting, or analyzing information.
Regardless of the kind of information they contain, all paragraphs share certain characteristics.
One of the most important of these is a topic sentence.
SCIENTISTS HAVE LEARNED TO SUPPLEMENT THE SENSE OF SIGHT IN NUMEROUS WAYS.
In front of the tiny pupil of the eye they put, on Mount Palomar, a great monocle 200 inches in diameter, and with it see 2000 times farther into the depths of space.