Meaning: 'State' refers to a particular condition or situation that something is in, especially in terms of physical or mental status.

Wrong options:

• path: The word 'path' implies a route or course, which does not relate to the concept of hibernation and is grammatically incorrect in this context.
• circumstance: The term 'circumstance' refers to a condition or fact that affects a situation, but it does not convey the specific idea of a mode of being like 'state' does.
• condition: While 'condition' could be relevant, it is less precise than 'state' in describing the specific phase of deep hibernation.

Correct answer: detect

Explanation: The verb 'detect' is appropriate here as it indicates the action of discovering or identifying the level of harmful molecules, fitting grammatically and contextually with the sentence structure.

Meaning: 'Detect' means to discover or identify the presence of something, particularly through observation or measurement.

Wrong options:

• amplify: The word 'amplify' means to increase or make something stronger, which does not fit the context of identifying harmful molecules.
• disable: 'Disable' means to make something unable to function, which is contrary to the action of identifying or measuring levels of molecules.
• introduce: The term 'introduce' implies bringing something into a situation, which does not align with the action of sensing or measuring.

Correct answer: are made of

Explanation: The phrase 'are made of' correctly indicates the composition of the sensors, fitting grammatically as it describes the material that constitutes the sensors in the present tense.

Meaning: 'Are made of' indicates what something consists of, specifically referring to the materials used to create the sensors.

Wrong options:

• made: The word 'made' is in the past tense and does not fit the present context of describing the sensors' composition.
• have been made: The phrase 'have been made' suggests a completed action in the past, which is not suitable for describing the current state of the sensors.
• made in: 'Made in' typically refers to the location of manufacture, which does not convey the composition of the sensors.

Correct answer: signals

Explanation: The verb 'signals' appropriately conveys the action of indicating or communicating a message, fitting grammatically and contextually as it describes what the change in structure does for the tardigrades.

Meaning: 'Signals' means to convey information or indicate something, particularly in a way that prompts a response or action.

Wrong options:

• infers: The word 'infers' means to deduce or conclude information from evidence, which does not fit the context of actively indicating a response.
• sustains: 'Sustains' means to support or maintain, which does not align with the action of indicating or signaling a change in behavior.
• identifies: The term 'identifies' means to recognize or establish what something is, which does not accurately describe the action of prompting a response.