Meaning: 'So' means 'to such a great extent' or 'very,' indicating that the gravitational pull is extremely powerful.

Wrong options:

• such: 'Such' is used to refer to a type or kind, which does not fit the context of describing the extent of gravitational pull here.
• some: 'Some' implies an unspecified amount but does not convey the intensity required in this context.
• somewhat: 'Somewhat' indicates a moderate degree, which contradicts the extreme nature of the gravitational pull being described.

Correct answer: exist

Explanation: The verb 'exist' appropriately indicates the presence of supermassive black holes at the centers of galaxies, fitting grammatically and contextually within the sentence structure.

Meaning: 'Exist' means to be present or to have reality, confirming that supermassive black holes are found in these locations.

Wrong options:

• release: 'Release' implies letting go or emitting something, which does not apply to the context of black holes being present.
• oppose: 'Oppose' means to resist or stand against, which is not relevant to the existence of black holes in galaxies.
• reform: 'Reform' suggests making changes or improvements, which does not fit the context of stating that black holes are present.

Correct answer: indicates

Explanation: The verb 'indicates' effectively conveys that evidence points to the existence of a supermassive black hole, fitting both grammatically and contextually within the sentence.

Meaning: 'Indicates' means to show or suggest something, in this case, the presence of a black hole in Messier 87.

Wrong options:

• shrinks: 'Shrinks' means to become smaller, which does not relate to the context of providing evidence about a black hole.
• overcomes: 'Overcomes' implies defeating or prevailing over something, which is not applicable in this context.
• swaps: 'Swaps' means to exchange, which does not fit the context of indicating evidence.

Correct answer: clues

Explanation: The word 'clues' fits well as it refers to pieces of information that help explain the formation and behavior of the black hole, aligning grammatically and contextually with the sentence.

Meaning: 'Clues' are hints or pieces of information that lead to understanding something better, in this case, the black hole's characteristics.

Wrong options:

• connections: 'Connections' implies relationships or links, which does not specifically convey the idea of information about formation and behavior.
• discriminations: 'Discriminations' refers to the ability to recognize differences, which is not relevant to the context of providing information about black holes.
• divisions: 'Divisions' suggests separations or classifications, which does not fit the context of shedding light on the formation and behavior of black holes.