Verification of truth: Milk necessarily contains which of the following? Choose the constituent that is always present.
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ASugar
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BFats
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CCalcium
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DWater
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ENone of these
Answer
Correct Answer: Water
Explanation
Introduction / Context:We identify a constituent present in all natural milk varieties. Processed variants (e.g., skim) alter proportions, so the attribute must remain true across types.
Given Data / Assumptions:
- “Milk” refers to natural mammalian milk (prior to dilution or dehydration).
- We compare universal vs. variable components.
Concept / Approach:Milk is an emulsion/colloid consisting predominantly of water with dissolved lactose (milk sugar), minerals (including calcium salts), proteins, and dispersed fat globules. Some components vary by species and processing; water is fundamental.
Step-by-Step Solution:
Sugar (lactose): typically present, but “lactose-free” processed milks hydrolyze lactose; variability exists.Fats: range from high-fat to skim (< 0.5% fat); near-zero-fat products exist.Calcium: characteristic but concentration varies; fortified alternatives blur the line in products.Water: forms the bulk medium in all natural milk; even “condensed” or “powdered” variants derive from removing water.Verification / Alternative check:Across mammals and processing states, water’s presence is definitional for liquid milk.
Why Other Options Are Wrong:
- Sugar/Fats/Calcium: variable quantities; processing can reduce or modify presence/form.
- None of these: incorrect because water is always present in milk.
Common Pitfalls:Taking “commonly present” (fat, lactose) as “necessarily present.”
Final Answer:Water