Meaning: 'Characteristics' refers to the distinguishing traits or features of something, in this case, the qualities that make hot Jupiters similar to the largest planet in our solar system.

Wrong options:

• borders: 'Borders' refers to the edges or boundaries of something, which does not relate to the qualities of planets.
• expressions: 'Expressions' typically refer to the way something is conveyed or shown, not applicable to the physical traits of planets.
• shapes: 'Shapes' denotes the form or outline of an object, which is too narrow a term to encompass the various features of planets.

Correct answer: planet

Explanation: The term 'planet' is the correct noun that fits the context of the sentence, as it directly refers to the largest celestial body in the solar system, making it grammatically and contextually appropriate.

Meaning: 'Planet' refers to a large celestial body that orbits a star, such as Earth or Jupiter, which is relevant in the context of comparing hot Jupiters to the largest planet in our solar system.

Wrong options:

• frame: 'Frame' refers to a structure that gives shape or support, which does not apply to celestial bodies.
• subordinate: 'Subordinate' describes something of lesser importance or rank, which is not relevant in this context.
• comet: 'Comet' refers to a small celestial body made of ice and dust, which is not comparable to a planet.

Correct answer: astronomers

Explanation: The word 'astronomers' is the correct noun that fits the context, as it refers to scientists who study celestial bodies, making it grammatically and contextually appropriate for the search for extrasolar worlds.

Meaning: 'Astronomers' are scientists who study stars, planets, and other celestial phenomena, which aligns perfectly with the context of searching for new worlds.

Wrong options:

• members: 'Members' refers to individuals belonging to a group, which does not specifically relate to the study of celestial bodies.
• parties: 'Parties' typically refer to groups of people involved in a particular activity, which is not relevant in this scientific context.
• makers: 'Makers' implies creators or builders, which does not fit the context of scientific exploration.

Correct answer: detect

Explanation: The verb 'detect' fits grammatically and contextually as it describes the action of discovering or identifying the presence of something, which is appropriate in the context of observing planets.

Meaning: 'Detect' means to discover or identify the existence of something, in this case, the presence of planets as they pass in front of their stars.

Wrong options:

• denounce: 'Denounce' means to publicly declare something as wrong or evil, which does not fit the context of observing celestial bodies.
• deflect: 'Deflect' means to cause something to change direction, which is not relevant to the act of observing or discovering planets.
• direct: 'Direct' means to guide or manage something, which does not apply to the context of identifying celestial bodies.