Meaning: 'Tranquil' means peaceful and calm, creating an environment that is conducive to good sleep.

Wrong options:

• bright: 'Bright' suggests a well-lit environment, which is counterproductive to sleep quality as it can be stimulating rather than calming.
• loud: 'Loud' indicates high noise levels, which would disrupt sleep rather than enhance it, making it an unsuitable choice.
• chaotic: 'Chaotic' implies disorder and confusion, which is the opposite of what is needed for a good sleep environment.

Correct answer: blue

Explanation: The term 'blue' light is specifically referenced in sleep studies as it can interfere with the body's natural sleep-wake cycle. This choice fits both grammatically and contextually, as it directly relates to the advice given about minimizing exposure to certain types of light before bedtime.

Meaning: 'Blue' light refers to a specific wavelength of light that can affect sleep patterns, particularly from screens and artificial lighting.

Wrong options:

• green: 'Green' light does not have the same negative impact on sleep as blue light, making it an incorrect choice in this context.
• ultraviolet: 'Ultraviolet' light is not typically discussed in relation to sleep and is more associated with skin damage, thus irrelevant here.
• infrared: 'Infrared' light is not visible to the human eye and does not have the same implications for sleep disruption as blue light.

Correct answer: sleep

Explanation: The word 'sleep' fits perfectly in this context as it directly refers to the routine being established for rest. It is grammatically correct and aligns with the overall theme of the passage, which focuses on improving sleep quality.

Meaning: 'Sleep' refers to the natural state of rest for the body and mind, which is crucial for health and well-being.

Wrong options:

• eating: 'Eating' does not relate to the routine that signals winding down for sleep, making it an inappropriate choice.
• workout: 'Workout' implies physical activity, which is not conducive to signaling bedtime and would not fit the context of a sleep routine.
• study: 'Study' suggests an activity that is mentally stimulating, which contradicts the idea of winding down for sleep.

Correct answer: close to

Explanation: The phrase 'close to' is grammatically correct and contextually appropriate as it indicates a time frame relative to bedtime. It effectively conveys the idea of avoiding certain activities just before going to sleep.

Meaning: 'Close to' means near in time, indicating that the actions should be avoided in the period leading up to bedtime.

Wrong options:

• close: 'Close' alone lacks the necessary preposition to indicate proximity in time, making it incomplete in this context.
• next to: 'Next to' implies physical proximity rather than temporal, which does not fit the context of time management before sleep.
• upon: 'Upon' suggests an immediate action rather than a time frame, making it unsuitable for indicating what should be avoided before bedtime.