What does the passage mainly discuss?

1.         What does the passage mainly discuss?

• The detail seen through a microscope

• Sources of illumination for microscopes

• A new kind of microscope

• Outdated microscopic technique

2.         According to the passage, the invention of the visible-light microscope allowed scientists to

• see viruses directly

• develop the electron microscope later on

• understand more about the distribution of the chemical elements

• discover single celled plants and animals they had never seen before

3.         The word "minuscule" in the first paragraph is closest in meaning to

• circular

• dangerous

• complex

• tiny

4.         The word "it" in in the first paragraph refers to

• a type of microscope

• human perception

• the natural world

• light

5.         Why does the author mention the visible light microscope in the first paragraph?

• To begin a discussion of sixteenth century discoveries

• To put the X-ray microscope in historical perspective

• To show how limited its uses are

• To explain how it functioned

6.         Why did it take so long to develop the X-ray microscope?

• Funds for research were insufficient

• The source of illumination was not bright enough until recently

• Materials used to manufacture X-ray tubes were difficult to obtain

• X-ray microscopes were too complicated to operate

7.         The word "enables" in the last paragraph is closest in meaning to

• constitutes

• specifies

• expands

• allows

8.         The word "Rather" in in the last paragraph is closest in meaning to

• significantly

• preferably

• somewhat

• instead

9.         The word "those" in in the last paragraph refers to

• properties

• investigations

• microscopes

• X-rays

10.     Based on the information in the passage, what can be inferred about X-ray microscopes in the future?

• They will probably replace electron microscopes altogether

• They will eventually be much cheaper to produce than they are now

• They will provide information not available from other kinds of microscopes

• They will eventually change the illumination range that they now use