Meaning: 'Diverged' means to have moved apart or gone in different directions, particularly in the context of species evolution.

Wrong options:

• converged: Converged means to come together, which contradicts the idea of humans separating from an ancestor.
• urged: Urged is a verb meaning to strongly encourage, which does not fit the context of evolutionary change.
• verged: Verged implies coming close to something, which does not accurately describe the separation from an ancestor.

Correct answer: flexible

Explanation: The word 'flexible' is appropriate here as it describes the tongue's ability to move easily and adapt, which is essential for precise control in speech. This matches the context of anatomical changes that enhance vocal capabilities.

Meaning: 'Flexible' means capable of bending easily without breaking, indicating the tongue's adaptability in movement.

Wrong options:

• irresistible: Irresistible means too attractive or appealing to be resisted, which does not relate to the physical properties of the tongue.
• ineligible: Ineligible means not qualified or suitable, which is irrelevant in this context of anatomical function.
• convertible: Convertible refers to something that can be changed into a different form, which does not apply to the tongue's movement.

Correct answer: pitch

Explanation: The word 'pitch' fits well as it refers to the perceived frequency of a sound, which is crucial in speech and singing. This aligns with the context of vocal capabilities and the changes in the human vocal tract.

Meaning: 'Pitch' refers to the highness or lowness of a sound, an essential aspect of vocalization.

Wrong options:

• ditch: Ditch refers to a narrow channel or to abandon something, which does not relate to vocal characteristics.
• impacts: Impacts means effects or influences, which is too vague and does not specifically refer to sound characteristics.
• state: State refers to a condition or situation, which does not fit the context of vocal modulation.

Correct answer: evolutionary

Explanation: The word 'evolutionary' is suitable as it pertains to the gradual development of species over time, which is the context of the changes discussed in the passage. It highlights the nature of the development being a result of evolutionary processes.

Meaning: 'Evolutionary' relates to the process of evolution, indicating changes that occur over generations.

Wrong options:

• imaginary: Imaginary means not real or fanciful, which does not apply to the biological changes discussed.
• preliminary: Preliminary means initial or preparatory, which does not accurately describe the ongoing process of evolution.
• visionary: Visionary refers to someone with foresight or imagination, which is unrelated to the biological context of development.