Which objective lens requires oil to be applied?
Multiple choice.

Choice A rationale: An isotonic solution has the same solute concentration as the plant cells, which means it has the same water potential. Water will move in and out of the plant cells at the same rate, causing them to remain unchanged in size and shape. This will not help the lettuce to become less wilted.

Choice B rationale: A hypertonic solution has a higher solute concentration than the plant cells, which means it has a lower water potential. Water will move out of the plant cells by osmosis, causing them to shrink and become plasmolysed. This will make the lettuce more wilted and not crisper.

Choice C rationale: Soaking the lettuce in water would have an effect, depending on the relative solute concentration of the water and the plant cells. Water will move across the cell membrane by osmosis, either into or out of the plant cells, causing them to change in size and shape.

Choice D rationale: A hypotonic solution has a lower solute concentration than the plant cells, which means it has a higher water potential. Water will move into the plant cells by osmosis, causing them to swell and become turgid. This will make the lettuce crisper and more appealing.

Choice E rationale: A hypotonic solution will cause the plant cells to gain water and become turgid, not more wilted. Wilted lettuce is caused by the loss of water from the plant cells, which makes them flaccid and soft.

Choice A rationale: Body tube is incorrect because the body tube is the part of the microscope that connects the eyepiece to the objective lenses, not the part that holds the objective lenses. The body tube is a hollow cylinder that allows the passage of light from the objective lenses to the eyepiece.

Choice B rationale: Stage is incorrect because the stage is the part of the microscope that supports the slide and the specimen, not the part that holds the objective lenses. The stage is a flat platform that has a hole in the center to allow the light source to illuminate the specimen.

Choice C rationale: Base is incorrect because the base is the part of the microscope that supports the whole microscope, not the part that holds the objective lenses. The base is the bottom part of the microscope that provides stability and balance.

Choice D rationale: Rotating nosepiece is correct because the rotating nosepiece is the part of the microscope that holds the objective lenses and allows them to be changed. The rotating nosepiece is a circular structure that has four or more objective lenses attached to it. The rotating nosepiece can be rotated to switch between different magnifications of the objective lenses.