Meaning: 'Decrease' means to make something smaller or less in amount, degree, or size, which in this context refers to the reduction of biodiversity due to invasive species.

Wrong options:

• sheets: The word 'sheets' is a noun referring to flat pieces of material, which does not fit the context of describing an action related to biodiversity.
• musketeers: The term 'musketeers' refers to soldiers armed with muskets, which is irrelevant in this ecological context.
• inductees: 'Inductees' refers to individuals who are formally admitted to a group or organization, which does not relate to the action of affecting biodiversity.

Correct answer: parasites

Explanation: The term 'parasites' is appropriate as it refers to organisms that live on or in a host, often harming it, which fits the context of species that keep invasive species in check.

Meaning: 'Parasites' are organisms that depend on another organism (the host) for survival, often causing harm, which is relevant to the discussion of ecological balance.

Wrong options:

• organs: 'Organs' are parts of an organism that perform specific functions, which does not fit the context of controlling invasive species.
• abodes: The word 'abodes' refers to places of residence, which is unrelated to the concept of ecological checks on invasive species.
• kinds: 'Kinds' is a general term for types or categories, which does not specifically relate to the controlling factors of invasive species.

Correct answer: freshwater

Explanation: The word 'freshwater' accurately describes the type of shrimp being studied, fitting grammatically as an adjective that specifies the habitat of the shrimp.

Meaning: 'Freshwater' refers to water that is not salty, typically found in rivers and lakes, which is relevant to the habitat of the shrimp in question.

Wrong options:

• leftover: 'Leftover' refers to something remaining after the rest has been used or dealt with, which does not apply to the type of shrimp being studied.
• narrower: The term 'narrower' is a comparative adjective that does not relate to the classification of shrimp or their habitat.
• shipowner: 'Shipowner' refers to a person or company that owns a ship, which is irrelevant in the context of discussing shrimp.

Correct answer: infected

Explanation: The word 'infected' is a past participle that describes the condition of the shrimp, fitting grammatically and contextually as it indicates the presence of a parasite affecting them.

Meaning: 'Infected' means having a disease or condition caused by pathogens, which in this case refers to shrimp carrying an intestinal worm.

Wrong options:

• affected: 'Affected' implies a change in state but does not specifically indicate the presence of a parasite, making it less precise in this context.
• feathered: The term 'feathered' describes something covered in feathers, which is irrelevant to the context of shrimp and parasites.
• connected: 'Connected' suggests a relationship or link, which does not accurately describe the condition of the shrimp in relation to the parasite.

Correct answer: constituted

Explanation: The word 'constituted' fits grammatically as it is a verb that describes the makeup or composition of the shrimp's body weight, aligning well with the context of the sentence.

Meaning: 'Constituted' means to be a part of or to make up something, which in this case refers to the worm making up a significant portion of the shrimp's body weight.

Wrong options:

• disputed: 'Disputed' means to argue against or question, which does not fit the context of describing the relationship between the worm and the shrimp's body weight.
• quintupled: The term 'quintupled' means to increase fivefold, which does not accurately describe the relationship of the worm's weight to the shrimp.
• fueled: 'Fueled' implies providing energy or motivation, which does not relate to the composition of the shrimp's body weight.