40.What does the second paragraph mainly discuss?
The Milky1 Way
Major categories of galaxies2
How elliptical galaxies are formed
Differences between irregular and spiral galaxies
41.The word whichin line 7refers to
dust
gas
pattern
galaxy3
42.According to the passage,new stars are formed in spiral galaxies due to
an explosion of gas
the compression of gas and dust
the combining of old stars
strong radio emissions4
43.The word symmetricalin line 9is closest in meaning to
proportionally balanced
commonly seen
typically large
steadily growing
44.The word obviousin line 10is closest in meaning to
discovered
apparent
understood
simplistic
45.According to the passage,which of the following is NOT true of elliptical galaxies?
They are the largest galaxies.
They mostly contain old stars.
They contain a high amount of interstellar gas.
They have a spherical5 shape.
46.Which of the following characteristics of radio galaxies is mentioned in the passage?
They are a type of elliptical galaxy.
They are usually too small to be seen with a telescope.
They are closely related to irregular galaxies.
They are not as bright as spiral galaxies.
47.What percentage of galaxies are irregular?
10%
25%
50%
75%
48.The word theyin line 21refers to
intervals
yardsticks
distances
galaxies
49.Why does the author mention the Virgo galaxy and the Andromeda galaxy in the third paragraph?
To describe the effect that distance has no visibility.
To compare the ages of two relatively6 young galaxies.
To emphasize the vast distances of the galaxies from Earth.
To explain why certain galaxies cannot be seen by a telescope.
50.The word dominatedin line 26is closest in meaning to
threatened
replaced
were developing in
were prevalent in
