A.I. Explanation:

Correct answer: makes

Explanation: The verb 'makes' fits grammatically as it agrees with the singular subject 'size' and indicates the action of enabling something, which is contextually appropriate here as it describes how their small size facilitates movement.

Meaning: 'Makes' means to cause or enable something to happen, indicating that their small size allows them to move easily.

Wrong options:

• does: 'Does' is a helping verb that does not convey the action of enabling, making it grammatically incorrect in this context.
• gets: 'Gets' implies receiving or obtaining, which does not fit the context of describing the effect of size on movement.
• has: 'Has' indicates possession and does not convey the action of facilitating movement, making it unsuitable here.

Correct answer: source

Explanation: The word 'source' is appropriate as it refers to the origin of food, fitting grammatically and contextually as it describes the unusual food that marmosets consume.

Meaning: 'Source' means the place or thing from which something originates, in this case, the food that marmosets obtain.

Wrong options:

• diet: 'Diet' refers to the kinds of food a person or animal usually eats, but it does not specifically indicate the origin of that food, making it less precise here.
• habit: 'Habit' refers to a regular practice or routine, which does not fit the context of food acquisition.
• process: 'Process' implies a series of actions or steps taken to achieve a particular end, which does not accurately describe the food itself.

Correct answer: branches

Explanation: The noun 'branches' fits grammatically as it is a plural noun that refers to parts of a tree, which is contextually relevant as it describes where the holes are left after marmosets extract sap.

Meaning: 'Branches' are the parts of a tree that grow out from the trunk, which is where marmosets dig for sap.

Wrong options:

• skin: 'Skin' refers to the outer covering of an animal or human, which does not relate to the context of trees and is grammatically incorrect here.
• mouth: 'Mouth' refers to the opening in the face used for eating, which is irrelevant to the context of tree sap extraction.
• ground: 'Ground' refers to the surface of the earth, which does not fit the context of where the holes are made in relation to the trees.

Correct answer: danger

Explanation: The noun 'danger' fits grammatically as it indicates a state of being at risk, which is contextually appropriate as it describes the serious threat to marmosets and tamarins due to habitat loss.

Meaning: 'Danger' means the possibility of suffering harm or injury, indicating the risk of extinction for these animals.

Wrong options:

• doubt: 'Doubt' refers to uncertainty and does not convey a state of risk or threat, making it contextually inappropriate here.
• trouble: 'Trouble' implies difficulty but lacks the specific connotation of risk associated with extinction, making it less precise.
• way: 'Way' refers to a method or manner of doing something, which does not fit the context of describing a state of risk.