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.

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

Explanation:

The structure found on the outside of the onion cell is the cell wall, which is specific to plants. The structure found on the outside of the skin cell is the cell membrane, which is found on all cells.

Structure X is not living, and structure Y is living.  - this is false, both animal and plant cells are living.

Structure X can be found in some human cells, and structure Y can be found in some plant cells.  - this is false, the opposite is true.

Structure X is only found in plant cells, and structure Y is found in plant and animal cells.  - this is true structure X is the plant cell wall, and structure Y is the cell membrane

Structure X is semipermeable, and structure Y is selectively permeable. Semi-permeable and selectively permeable are essentially the same thing - it means the barrier allows some substances to pass through but not others.

what are the options