Meaning: 'Liability' refers to a person or thing whose presence or behavior is likely to cause embarrassment or put one at a disadvantage, in this case, referring to male chicks being a burden to farmers.

Wrong options:

• maintainability: This term refers to the ease of maintaining something, which does not apply to the context of male chicks being a burden.
• digestibility: This term relates to how easily food can be digested, which is irrelevant in this context as it does not pertain to the economic or operational impact on farmers.
• sensibility: This term refers to the ability to appreciate and respond to complex emotional or aesthetic influences, which does not fit the context of discussing the economic implications of male chicks.

Correct answer: sort

Explanation: The verb 'sort' is appropriate here as it describes the action of categorizing or separating male chicks from females, which is a necessary task for farmers shortly after hatching. It fits grammatically and contextually, as it directly relates to the process described in the passage.

Meaning: 'Sort' means to arrange or separate items based on specific criteria, in this case, distinguishing male chicks from female chicks.

Wrong options:

• tort: This term refers to a wrongful act leading to legal liability, which does not fit the context of categorizing chicks.
• snort: This term refers to a sound made by forcing air through the nose, which is irrelevant in this context.
• port: This term generally refers to carrying or transporting something, which does not apply to the action of separating chicks.

Correct answer: culling

Explanation: The word 'culling' is the correct choice as it specifically refers to the selective removal of animals from a group, which is the action being described in the context of male chicks being killed due to their lack of commercial value. It fits both grammatically and contextually within the sentence.

Meaning: 'Culling' means to select and remove animals from a group, often for reasons related to health or productivity, in this case, referring to the mass killing of male chicks.

Wrong options:

• sliding: This term refers to moving smoothly along a surface, which does not relate to the context of removing chicks.
• pulling: This term means to exert force on something to move it towards oneself, which does not fit the context of the passage.
• curling: This term refers to forming into a spiral or curved shape, which is irrelevant to the action of removing male chicks.

Correct answer: breed

Explanation: The verb 'breed' is suitable here as it refers to the process of producing offspring, which is the action being taken by researchers to create gene-edited hens. It fits grammatically and contextually, as it describes the scientific endeavor of producing hens that lay specific types of eggs.

Meaning: 'Breed' means to produce offspring, particularly in a controlled manner, in this case, referring to the creation of hens that lay eggs with only female embryos.

Wrong options:

• deed: This term refers to an action or a legal document, which does not fit the context of producing chicks.
• greed: This term refers to an intense and selfish desire for something, especially wealth, which is irrelevant in this context.
• creed: This term refers to a system of religious belief, which does not relate to the biological process of producing chicks.