Meaning: A 'birdfeeder' is a device or container used to provide food for birds, typically placed in gardens or backyards.

Wrong options:

• beaver: A 'beaver' is a type of animal and does not fit contextually as it does not relate to feeding birds or the setting described.
• believer: A 'believer' refers to a person who has faith in something, which is unrelated to the context of evolution or feeding birds.
• phonier: A 'phonier' is someone who is not genuine, which does not relate to the context of the sentence about evolution and feeding.

Correct answer: blackcaps

Explanation: The word 'blackcaps' is the correct term as it refers to a specific species of birds, fitting grammatically as a plural noun that matches the context of the study about birds in Europe. It is also contextually relevant as the text discusses a particular kind of warbler.

Meaning: 'Blackcaps' are a type of songbird known for their distinctive black caps on their heads, commonly found in Europe.

Wrong options:

• pox: 'Pox' refers to a type of disease and does not fit the context of discussing a species of birds.
• flaps: 'Flaps' is a verb or noun related to movement and does not refer to a specific bird species, making it contextually irrelevant.
• chats: 'Chats' refers to a different group of birds and does not specifically identify the species being studied.

Correct answer: distinct

Explanation: The word 'distinct' is an adjective that describes the two groups of blackcaps as being clearly different from one another, fitting grammatically and contextually within the sentence structure.

Meaning: 'Distinct' means clearly different or unique, indicating that the two groups of blackcaps have diverged in behavior or characteristics.

Wrong options:

• bit: A 'bit' is a small amount and does not fit grammatically or contextually as it does not describe the groups of birds.
• disconnect: A 'disconnect' refers to a lack of connection and does not appropriately describe the relationship between the two groups of birds.
• split: 'Split' is a verb that does not fit grammatically in this context, as the sentence requires an adjective to describe the groups.

Correct answer: populations

Explanation: The term 'populations' is a noun that refers to groups of individuals of the same species, fitting grammatically and contextually as it describes the two groups of blackcaps that have diverged.

Meaning: 'Populations' refers to groups of organisms of the same species living in a particular area, in this case, the two groups of blackcaps.

Wrong options:

• elevators: 'Elevators' are mechanical devices for lifting and do not relate to the context of bird species or groups.
• breakers: 'Breakers' can refer to waves or devices that break something, which is unrelated to the context of bird populations.
• contraindications: 'Contraindications' refer to reasons not to use a particular treatment or procedure, which does not fit the context of discussing bird groups.

Correct answer: starting

Explanation: The word 'starting' is a verb that indicates the beginning of a process, fitting grammatically and contextually as it describes the blackcaps beginning to show differences from one another.

Meaning: 'Starting' means beginning or commencing, indicating that the blackcaps are beginning to evolve differently.

Wrong options:

• blotting: 'Blotting' refers to the act of absorbing liquid and does not fit contextually as it does not relate to the evolution of birds.
• wanting: 'Wanting' implies a desire for something and does not fit grammatically or contextually in this sentence about evolution.
• padding: 'Padding' refers to adding material for comfort or protection, which is irrelevant to the context of bird evolution.

Correct answer: narrower

Explanation: The word 'narrower' is a comparative adjective that describes the beaks of the blackcaps as being less wide, fitting grammatically and contextually as it describes a physical characteristic that has evolved due to their feeding habits.

Meaning: 'Narrower' means having a smaller width, indicating that the beaks of the blackcaps that winter in England are adapted differently than those that go south.

Wrong options:

• freshwater: 'Freshwater' refers to water that is not salty and does not fit the context of describing beak characteristics.
• spillover: 'Spillover' refers to an overflow or excess and does not relate to the physical description of bird beaks.
• scheduler: 'Scheduler' refers to a person or tool that organizes time and does not fit the context of describing bird anatomy.