5 Answer: H

Question type: Matching Features

Answer location: Paragraph 9, line 8

Answer explanation: The 8th line of the 9th paragraph states that the gravitational field of a black hole is powerful enough to prevent the escape of light and is so dense that it cannot be measured. These lines suggest that the gravitational field of a black hole is extremely powerful to prevent the escape of light and is very dense making it unable to measure. Thus, the size of the black hole is immeasurable. So, the answer is H.

6 Answer: E

Question type: Matching Features

Answer location: Paragraph 7, line 4

Answer explanation: The 4th line of paragraph 7 states that the white star will shine white-hot until the remaining energy (thermal energy trapped in its interior) has been exhausted after which it will no longer emit light. This can take in excess of several billion years. It is then termed a black dwarf (a cold, dark star, perhaps replete with diamonds) and remains in that stage forever. These lines indicate that the white star will brightly shine until the energy gets trapped after which it doesn’t emit light. This takes a billion years and is referred to as a black dwarf, which remains in the same stage forever. Thus, the answer is E.

7 Answer: nuclear fusion

Question type: Sentence Completion

Answer location: Paragraph 4

Answer explanation: The initial lines of paragraph 4 reveals that as it glows, hydrogen in the center (through nuclear fusion) becomes helium. These lines indicate that hydrogen will turn into helium after nuclear fusion occurs. Thus, the answer is nuclear fusion.

8 Answer: core

Question type: Sentence Completion

Answer location: Paragraph 6

Answer explanation: Paragraph 6 states that throughout the red giant phase, the hydrogen in the outer parts carries on burning, and the center gets hotter and hotter. On reaching 200,000,000°C, the helium atoms fuse forming carbon atoms. The remainder of the hydrogen explodes and forms a ring around the core called a planetary nebula. We can understand from these lines that the hydrogen in the outer parts throughout the red giant phase carries on burning, resulting in the center becoming hot and when it reaches a greater temperature, the helium atoms fuse forming carbon atoms and the remaining hydrogen explodes and forms a ring around the core called a planetary nebula. Thus, the color of the red giant is formed as the core becomes smaller and the outer areas cool. So, the answer is core.

9 Answer: starts to die

Question type: Sentence Completion

Answer location: Paragraph 6 – 7

Answer explanation: Paragraph 6 reveals that the helium atoms fuse forming carbon atoms when it reaches 200,000,000°C and the remainder of the hydrogen explodes and forms a ring around the core called a planetary nebula. While the initial lines of the 7th paragraph state that when the final helium atoms have fused into carbon atoms with medium-sized stars, the star starts to die. These lines indicate that when the temperature reaches 200,000,000 C, the star’s helium atoms fuse into carbon atoms, and then the star starts to die. Thus, the answer is, starts to die.

10 Answer: collapse

Question type: Sentence Completion

Answer location: Paragraph 8

Answer explanation: Paragraph 8 states that when the larger red giants (massive stars) collapse, which happens in an instant, so much planetary nebula is created that this gas and dust can be used as a building material for planets in developing solar systems. These lines suggest that unlike small and medium-sized, large stars collapse instantly that several planetary nebulae are created. Thus, the answer is collapse.

11 Answer: the gravitational field

Question type: Sentence Completion

Answer location: Paragraph 7, line 8

Answer explanation: The 8th line of the 7th paragraph illustrates that the gravitational field of a black hole is powerful enough to prevent the escape of light and is so dense that it cannot be measured. We can deduce from these lines that a black hole’s gravitational field is so powerful that it prevents the escape of light and is very dense, making it immeasurable. Thus, the answer is the gravitational field.

12 Answer: black holes

Question type: Sentence Completion

Answer location: Paragraph 7,last line

Answer explanation: The last line of paragraph 7 reveals that Wheeler came up with this name two years before the proof of the existence of the first black hole, X-ray binary star Cygnus X-1, in 1971. Astronomers think that there may be a black hole at the center of each galaxy. These lines suggest that Wheeler came up with the name before the proof of the existence of the first black hole. As a result, the Astronomers believe that there might be a black at the center of each galaxy. Thus, Astronomers knew about the black hole before they were able to confirm its existence. Therefore, the answer is a black hole.

13 Answer: debris/ materials

Question type: Sentence Completion

Answer location: Paragraph 10

Answer explanation: Paragraph 10 illustrates the fact that the life cycle of a star is really that — the materials from an exploded star mix with the hydrogen of the universe. This mixture, in turn, will be the starting point of the next star. The Sun is a case in point, containing the debris from numerous other stars that exploded long before the Sun was born. We can understand from these lines that the materials from an exploded star are mixed with the hydrogen of the universe, which in turn will be the initial point of the next star. In this case, the Sun contains debris from several other stars that exploded long before the existence of the Sun. Therefore, the planets and stars are likely to consist of debris/ materials from exploded celestial bodies. So, the answer is debris/materials.