Direction: In each of the following questions, a short passage is given with one of the lines in the passage missing and represented by a blank. Select the best out of the five answer choices given, to make the passage complete and coherent.
For hundreds of years, telescopes were the only instruments available for studying the planets and stars. Rapid advances in astrophysics and optical technology, coupled with the advent of the space age, broadened telescope technology in the last quarter of the 20th century. Astronomical telescopes now come in a wide variety of shapes and sizes, dictated largely by the portion of the electromagnetic spectrum the telescope is designed to view. ___________________________________.
1
Telescopes today view the entire spectrum of electromagnetic radiation sweeping the universe.
2
Telescopes are typically used to observe the skies.
3
A telescope is an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation.
4
The fundamental optical principles were first described in the 13th century by English scientist Roger Bacon.
5
News of the telescope's discovery spread rapidly through Europe.