Ascientist is comparing the outer structure of an onion cell, structure x, to the outer structure of a human skin cell, structure y. which generalization is true about the types of structures being examined? structure x is not living, and structure y is living. structure x can be found in some human cells, and structure y can be found in some plant cells. structure x is only found in plant cells, and structure y is found in plant and animal cells. structure x is semipermeable, and structure y is selectively permeable.