Meaning: 'Stable' means not changing or fluctuating; it suggests that the percentage of left-handed individuals remains constant over time.

Wrong options:

• even: 'Even' implies a level surface or equality, which does not convey the idea of consistency over time as required in this context.
• continual: 'Continual' suggests something that happens repeatedly over time, but it does not imply stability or lack of fluctuation, making it unsuitable here.
• similar: 'Similar' indicates likeness but does not convey the idea of a fixed or unchanging state, which is necessary for this sentence.

Correct answer: runs

Explanation: The verb 'runs' is appropriate here as it indicates that handedness is a trait that is passed down through generations, fitting the context of familial traits. It suggests a continuous process, which aligns with the meaning intended in the sentence.

Meaning: 'Runs' in this context means to occur or be transmitted, particularly in the sense of genetic traits being passed through families.

Wrong options:

• happens: 'Happens' is too vague and does not convey the idea of a trait being inherited or passed down, which is the focus of the sentence.
• is: 'Is' is a linking verb that does not provide the action or process of transmission that 'runs' does, making it less suitable in this context.
• occurs: 'Occurs' is similar to 'happens' and lacks the connotation of inheritance or familial transmission that 'runs' provides.

Correct answer: function

Explanation: The term 'function' is grammatically correct as it refers to the role or activity of the brain, fitting well within the context of discussing brain asymmetry and its implications. It indicates what the brain does, which is crucial for understanding the subsequent information about language and thought.

Meaning: 'Function' refers to the specific activities or roles that the brain performs, such as processing language and thought.

Wrong options:

• memory: 'Memory' refers specifically to the ability to store and recall information, which does not encompass the broader activities of the brain as 'function' does.
• size: 'Size' pertains to the physical dimensions of the brain, which is unrelated to the activities or roles it performs, making it contextually irrelevant here.
• capacity: 'Capacity' refers to the maximum amount that something can contain or perform, but it does not directly address the roles or activities of the brain as 'function' does.

Correct answer: significant

Explanation: The word 'significant' is appropriate as it indicates a noteworthy or considerable number of left-handers with specific language dominance patterns. It fits grammatically and contextually, emphasizing the importance of the number being discussed.

Meaning: 'Significant' means important or noteworthy, suggesting that the number of left-handers with certain language characteristics is considerable enough to be of interest.

Wrong options:

• maximum: 'Maximum' implies the greatest possible amount, which does not fit the context of discussing a noteworthy number, as it suggests a limit rather than a notable quantity.
• suggestive: 'Suggestive' implies that something indicates or hints at something else, which does not convey the idea of quantity or importance as effectively as 'significant' does.
• countable: 'Countable' refers to something that can be counted, but it lacks the connotation of importance or relevance that 'significant' provides.

Correct answer: searching

Explanation: The verb 'searching' is suitable as it indicates an active pursuit of knowledge or information regarding links to other conditions. It fits grammatically and contextually, emphasizing the ongoing effort of scientists in their research.

Meaning: 'Searching' means actively looking for or investigating something, in this case, the connections between left-handedness and other conditions.

Wrong options:

• researching: 'Researching' is a more formal term that implies a systematic investigation, but it does not convey the active pursuit aspect as effectively as 'searching' does in this context.
• detecting: 'Detecting' implies discovering something that is hidden or not immediately obvious, which does not fit the context of scientists looking for links, as it suggests a passive rather than active approach.
• inquiring: 'Inquiring' suggests asking questions or seeking information, but it lacks the active connotation of searching for specific links, making it less suitable in this context.