Meaning: 'Popular' means well-liked or favored by many people, indicating that dogs are cherished companions.

Wrong options:

• pretence: 'Pretence' refers to an attempt to make something that is not the case appear true, which does not fit the context of describing dogs.
• pounce: 'Pounce' is a verb meaning to spring or leap suddenly, which is unrelated to the description of dogs as companions.
• poster: 'Poster' is a noun referring to a printed picture or notice, which does not relate to the context of companionship.

Correct answer: domesticated

Explanation: The term 'domesticated' is the correct choice as it refers to the process of taming animals for human use, fitting the context of the sentence about the origins of the friendship between dogs and humans. It is a past participle that aligns with the passive construction of the sentence.

Meaning: 'Domesticated' means trained or adapted for living with humans, indicating that dogs have been bred and raised to live alongside people.

Wrong options:

• delegate: 'Delegate' means to assign responsibility to someone else, which does not fit the context of animal training.
• donated: 'Donated' refers to giving something as a gift, which is not relevant to the process of taming animals.
• deters: 'Deters' means to discourage someone from doing something, which does not apply to the context of animal domestication.

Correct answer: flourish

Explanation: The word 'flourish' fits well as it indicates thriving or prospering, which is contextually appropriate when discussing how dogs have adapted their diet. It is a verb that conveys a positive outcome of their evolution.

Meaning: 'Flourish' means to grow or develop in a healthy or vigorous way, suggesting that dogs thrive on a carbohydrate-rich diet.

Wrong options:

• fasten: 'Fasten' means to attach or secure, which does not relate to dietary habits.
• felony: 'Felony' refers to a serious crime, which is irrelevant in the context of discussing dietary adaptations.
• finding: 'Finding' is a noun or gerund that does not convey the idea of thriving or adapting in this context.

Correct answer: aiding

Explanation: The word 'aiding' is appropriate as it describes the act of helping or assisting, which fits the context of dogs supporting individuals with disabilities. It is a gerund that complements the structure of the sentence.

Meaning: 'Aiding' means providing help or support, indicating the role of dogs in assisting people with disabilities.

Wrong options:

• appeal: 'Appeal' refers to a request for help or a quality that attracts interest, which does not fit the context of assistance.
• announce: 'Announce' means to make something known publicly, which is unrelated to the supportive role of dogs.
• aloud: 'Aloud' means to speak or read out loud, which does not relate to the context of aiding individuals.

Correct answer: improved

Explanation: The word 'improved' fits grammatically as it describes the enhancement of energy levels, aligning with the positive effects of interacting with dogs. It is a past participle that complements the structure of the sentence.

Meaning: 'Improved' means made better or enhanced, indicating that patients experience better energy levels through interaction with dogs.

Wrong options:

• idle: 'Idle' means not active or not engaged, which contradicts the idea of increased energy levels.
• ignore: 'Ignore' means to pay no attention to something, which does not fit the context of discussing positive impacts.
• illuminates: 'Illuminates' means to light up or clarify, which does not relate to the concept of energy levels.