Question

a scientist 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.

Explanation:

Structure X is the cell wall of the onion plant cell, which is unique to plant cells. Structure Y is the cell membrane of the human skin cell, which is present in both plant and animal cells (plant cells have both a cell wall and cell membrane).

• The first option is wrong: the cell wall (X) is non-living, but the cell membrane (Y) is living, so this is reversed.
• The second option is wrong: cell walls (X) do not exist in human cells, and cell membranes (Y) are in all plant cells, not just some.
• The fourth option is wrong: both the cell wall (X) and cell membrane (Y) are selectively/semipermeable, so this distinction is incorrect.

Answer:

Structure X is only found in plant cells, and structure Y is found in plant and animal cells.