True because the plant is the leaves on top of the carrot and radish and the carrots and radishes are picked from under the ground
I think what they rely on is there experiment and how they do it
It would be best to ask a professional on the subject.
Both glycerophospholipids and sphingolipid structures are asymmetrically distributed in the two layers of the phospholipid bilayer. Sphingolipids are membrane lipids that have a ceramide backbone while glycerophospholipid has glycerol present in its membrane lipids. Sphingolipids may or may not be present.