Understanding Zebra Characteristics and Fill-in-the-Blanks

This question asks us to complete a description about zebras by selecting the most appropriate words to fill two blanks. The passage describes zebras as stocky wild horses, mentions their diet and habitat, and discusses the appearance and potential function of their stripes.

Analyzing the First Blank: Zebra Diet

The first blank is in the sentence: "These mostly ______ on grass." This sentence describes what zebras eat. We need a verb that correctly fits the context of animals consuming food, specifically grass.

• Option 1 uses "food". "food on grass" is grammatically incorrect. 'Food' is a noun.
• Option 2 uses "feed". "feed on grass" is a common and correct phrase used to describe the diet of grazing animals like zebras.
• Option 3 uses "serve". "serve on grass" does not make sense in this context. 'Serve' typically refers to presenting food or performing a duty.
• Option 4 uses "eat". "eat on grass" is grammatically possible, but "feed on" is the more standard and natural phrase when describing what an animal habitually consumes as its primary diet.

Comparing the options, "feed on grass" is the most appropriate and commonly used phrase for describing the grazing behavior of zebras.

Analyzing the Second Blank: Zebra Stripes

The second blank is in the sentence: "The zebra’s stripes are broken up with an ______ outline making it very difficult to spot them against a background of tall grass." This sentence discusses the appearance of zebra stripes and their effect on visibility (camouflage or disruptive coloration). We need an adjective that describes the nature of the outline of the stripes which contributes to making the zebra hard to spot.

• Option 1 uses "boundary". "boundary outline" refers to the edge, which is redundant with 'outline'. It doesn't describe the effect.
• Option 2 uses "effective". "effective outline" suggests that the way the stripes break up the outline is successful or good at achieving a certain outcome – in this case, making the zebra difficult to spot. This fits the context, implying the outline is effective at disrupting the animal's shape against the background.
• Option 3 uses "imaginary". "imaginary outline" suggests the outline isn't real, which contradicts the description of physical stripes.
• Option 4 uses "affective". "affective outline" relates to emotions or mood and is completely out of place in this biological description.

The word "effective" best describes how the stripe's outline functions to make the zebra difficult to spot, which relates to camouflage or disruptive coloration theories.

Selecting the Most Appropriate Option

Based on the analysis of both blanks, Option 2 provides the most appropriate words: "feed" for the first blank and "effective" for the second blank.

• "These mostly feed on grass." - Correct use of "feed on" for diet.
• "The zebra’s stripes are broken up with an effective outline making it very difficult to spot them against a background of tall grass." - "Effective" describes how the stripe pattern helps break up the shape.

Therefore, Option 2 is the most appropriate choice to fill the blanks correctly.

Revision Table: Key Zebra Terms

Additional Information on Zebra Biology

Zebras are iconic animals of the African continent, known for their distinctive black and white stripes. They are herbivores, meaning their diet consists primarily of plants, with grass being a major component, which is why the term "feed on grass" is used.

The purpose of zebra stripes has been a subject of scientific debate for many years. While camouflage against tall grass is one theory (disruptive coloration making it hard for predators to pick out individual zebras), other theories include:

• Predator confusion: Dazzling effect when zebras run in herds, making it hard for predators to single out one individual.
• Insect repellent: Stripes may deter biting insects like tsetse flies, which are vectors for diseases.
• Thermoregulation: Black and white stripes might help manage body temperature in hot environments.
• Social recognition: Individual stripe patterns might help zebras recognize each other.

The passage focuses on the disruptive camouflage aspect, suggesting the outline created by the stripes effectively breaks up the zebra's shape against its grassy habitat, making it difficult for predators to spot them easily.