Meaning: 'With' indicates the method or means of assistance in this context.

Wrong options:

• on: The preposition 'on' suggests a surface or topic, which does not fit the context of alleviating pain and swelling.
• of: The preposition 'of' indicates possession or relation, which does not convey the intended meaning of assistance here.
• to: The preposition 'to' indicates direction or purpose, which does not appropriately connect to the nouns 'pain' and 'swelling.'
• by: The preposition 'by' indicates the agent performing an action, which does not fit the context of helping with pain and swelling.
• far: The word 'far' is an adverb indicating distance, which is irrelevant in this context.
• in: The preposition 'in' indicates location or inclusion, which does not apply to the action of helping with pain.
• for: The preposition 'for' indicates purpose, which does not accurately describe the relationship to pain and swelling.

Correct answer: in

Explanation: The preposition 'in' is used to indicate the location of the knot within the muscle. It fits grammatically and contextually as it specifies where the vigorous massage is applied.

Meaning: 'In' indicates the position or location of the knot within the muscle.

Wrong options:

• on: The preposition 'on' suggests a surface, which does not accurately describe the location of the knot within the muscle.
• with: The preposition 'with' indicates accompaniment, which does not specify the location of the knot.
• to: The preposition 'to' indicates direction or purpose, which does not fit the context of location.
• by: The preposition 'by' indicates proximity or agency, which does not apply to the location of the knot.
• far: The word 'far' is an adverb indicating distance, which is irrelevant in this context.
• for: The preposition 'for' indicates purpose, which does not accurately describe the location of the knot.

Correct answer: to

Explanation: The preposition 'to' is used here to indicate the direction of the action of relaxing. It fits grammatically as it connects the verb 'help' to the infinitive 'relax.'

Meaning: 'To' is used to indicate the infinitive form of the verb, showing the purpose of the help provided.

Wrong options:

• on: The preposition 'on' suggests a surface or topic, which does not fit the context of the action of relaxing.
• with: The preposition 'with' indicates accompaniment, which does not convey the intended meaning of direction towards relaxing.
• in: The preposition 'in' indicates location or inclusion, which does not apply to the action of relaxing.
• by: The preposition 'by' indicates the means of doing something, which does not fit the context of helping to relax.
• far: The word 'far' is an adverb indicating distance, which is irrelevant in this context.
• for: The preposition 'for' indicates purpose, which does not accurately describe the direction of the action.

Correct answer: on

Explanation: The preposition 'on' is used to indicate the focus or topic of the action of strengthening and stretching. It fits grammatically as it connects the action to the subjects being worked on.

Meaning: 'On' indicates the subject or focus of the action, in this case, strengthening and stretching the muscles.

Wrong options:

• with: The preposition 'with' indicates accompaniment, which does not specify the focus of the action.
• to: The preposition 'to' indicates direction or purpose, which does not fit the context of working on strengthening and stretching.
• in: The preposition 'in' indicates location or inclusion, which does not apply to the action of working on muscles.
• by: The preposition 'by' indicates the means of doing something, which does not fit the context of focusing on strengthening and stretching.
• far: The word 'far' is an adverb indicating distance, which is irrelevant in this context.
• for: The preposition 'for' indicates purpose, which does not accurately describe the focus of the action.

Correct answer: for

Explanation: The preposition 'for' is used to indicate the purpose of the stretching. It fits grammatically as it connects the action of focusing to the intended outcome of stretching.

Meaning: 'For' indicates the purpose or intended outcome of the action, in this case, stretching.

Wrong options:

• on: The preposition 'on' suggests a surface or topic, which does not fit the context of indicating purpose for stretching.
• with: The preposition 'with' indicates accompaniment, which does not convey the intended meaning of purpose in this context.
• to: The preposition 'to' indicates direction or purpose, but does not accurately describe the purpose of stretching here.
• by: The preposition 'by' indicates the means of doing something, which does not fit the context of indicating purpose.
• far: The word 'far' is an adverb indicating distance, which is irrelevant in this context.
• in: The preposition 'in' indicates location or inclusion, which does not apply to the purpose of stretching.