Meaning: 'Crowding' refers to the act of gathering closely together, particularly in a confined space, which in this context relates to people moving into cities.

Wrong options:

• committing: The term 'committing' is a gerund that implies a promise or dedication to an action, which does not fit the context of people moving into cities.
• turning: 'Turning' is a gerund that suggests a change in direction or position, which does not accurately describe the action of people entering cities.
• living: 'Living' is a noun that refers to the state of being alive, but it does not convey the action of moving into cities.
• treaties: 'Treaties' are formal agreements between parties, which is unrelated to the context of urban migration.
• means: 'Means' is a noun that refers to a method or way of doing something, but it does not describe the action of crowding into cities.
• rigors: 'Rigors' is a noun that refers to harsh or demanding conditions, which does not fit the action of people entering urban areas.

Correct answer: means

Explanation: The word 'means' serves as a noun that indicates a method or resource. In this context, it suggests that food and diet evolved beyond just being a method for survival, fitting grammatically and contextually.

Meaning: 'Means' refers to a method or way of achieving something, particularly in the context of survival and sustenance.

Wrong options:

• living: 'Living' refers to the state of being alive, which does not fit as a method or resource in this context.
• treaties: 'Treaties' are formal agreements and do not relate to the concept of food as a method for survival.
• crowding: 'Crowding' is a gerund that describes an action, not a method or resource, making it unsuitable here.
• committing: 'Committing' is a gerund that implies dedication to an action, which does not fit the context of food as a means of survival.
• turning: 'Turning' is a gerund that suggests a change, which does not relate to the concept of food as a method for survival.
• rigors: 'Rigors' refers to harsh conditions, which does not fit the context of food being a method for survival.

Correct answer: rigors

Explanation: The term 'rigors' is a noun that refers to the demanding and harsh conditions of factory work. It fits grammatically and contextually, as it describes the challenges faced by workers in industrial settings.

Meaning: 'Rigors' refers to the harsh and demanding conditions that require adaptation, particularly in the context of labor-intensive jobs.

Wrong options:

• living: 'Living' refers to the state of being alive and does not relate to the conditions of factory work.
• treaties: 'Treaties' are formal agreements and do not pertain to the challenges of factory work.
• crowding: 'Crowding' describes an action and does not fit as a descriptor of conditions in the workplace.
• committing: 'Committing' is a gerund that implies dedication to an action, which does not fit the context of describing work conditions.
• means: 'Means' refers to a method or resource, which does not accurately describe the challenges of factory work.
• turning: 'Turning' is a gerund that suggests a change, which does not relate to the conditions faced in factory work.

Correct answer: living

Explanation: The word 'living' is a noun that refers to the means of earning a livelihood. It fits grammatically and contextually, as it describes how people earn their sustenance in the workforce.

Meaning: 'Living' refers to the means of supporting oneself financially, particularly through work.

Wrong options:

• treaties: 'Treaties' are formal agreements and do not relate to the concept of earning a livelihood.
• means: 'Means' refers to methods or resources, which does not specifically denote the act of earning a livelihood.
• crowding: 'Crowding' describes an action and does not fit as a noun related to earning a living.
• committing: 'Committing' is a gerund that implies dedication to an action, which does not fit the context of earning a livelihood.
• turning: 'Turning' is a gerund that suggests a change, which does not relate to the concept of earning a living.
• rigors: 'Rigors' refers to harsh conditions, which does not fit the context of earning a livelihood.