Answer: It contains a lower concentration of lipids than oil.
Explanation:
Lipids produce grease on paper because they cannot evaporate easily at room temperature. So, the “intensity” or definition of a greasy stain left behind by a substance can be a good indicator of its lipid content.
Solution 4, the oil, left a “definite greasy stain”, so it can be discerned that it has a considerable lipid content. However, solution 2, the milk, left only “a faint stain” behind.
If solution 2 had a lipid content equal to or higher than solution 4, it would have left a greasy stain that was identical or even more defined than the one left by the oil. If it had no lipid content, no stain would have been left behind.
So, it must have some lipids, but not an equal or higher concentration of lipids than that of the oil.
Then, the correct response must be that solution 2, the milk, contains a lower lipid content than solution 4, the oil.
Hope this helps!
