The total magnification achieved using a 10× objective lens with a 10× eyepiece lens is 20×.

True or False?

Choice A rationale: Up and down is incorrect because the mechanical stage upper knob does not control the vertical movement of the stage. The vertical movement of the stage is controlled by the coarse and fine adjustment knobs, which are located on the side of the microscope. The coarse adjustment knob is used to raise or lower the stage quickly, while the fine adjustment knob is used to fine-tune the focus of the specimen.

Choice B rationale: Right and left is correct because the mechanical stage upper knob controls the horizontal movement of the stage along the x-axis. The mechanical stage is a platform that holds the slide and the specimen, and it can be moved by two knobs that are located below the stage. The upper knob moves the stage right or left, while the lower knob moves the stage forward or backward.

Choice C rationale: Back and forth is incorrect because the mechanical stage upper knob does not control the horizontal movement of the stage along the y-axis. The horizontal movement of the stage along the y-axis is controlled by the mechanical stage lower knob, which is located below the stage and next to the upper knob. The lower knob moves the stage forward or backward, while the upper knob moves the stage right or left.

Choice D rationale: All of the answer choices are correct is incorrect because only one of the answer choices is correct. The mechanical stage upper knob only causes the stage to move right or left, not up and down or back and forth. The other movements of the stage are controlled by different knobs.

Choice A rationale: H2O is a reactant or input for the light reaction of photosynthesis. In the light reaction, water is split by the energy from sunlight in photosystem II, releasing electrons, protons, and oxygen. The electrons and protons are used to reduce NADP+ to NADPH and to synthesize ATP from ADP and Pi. The oxygen is either used for respiration or released into the air¹².

Choice B rationale: Oxygen is not a reactant or input for the light reaction of photosynthesis, but a product or output. Oxygen is released as a by-product of the splitting of water in photosystem II. Oxygen is either used for respiration or released into the air¹².

Choice C rationale: NADPH is not a reactant or input for the light reaction of photosynthesis, but a product or output. NADPH is an electron carrier that is reduced by the electrons from water in photosystem I. NADPH provides electrons and hydrogen for the dark reaction, which uses CO2 to produce glucose¹².

Choice D rationale: ATP is not a reactant or input for the light reaction of photosynthesis, but a product or output. ATP is an energy molecule that is synthesized by the enzyme ATP synthase using the proton gradient created by the electron transport chain. ATP provides energy for the dark reaction, which uses CO2 to produce glucose¹².

Choice E rationale: Carbon dioxide is not a reactant or input for the light reaction of photosynthesis, but a reactant or input for the dark reaction. The dark reaction uses CO2 and energy intermediates from the light reaction to produce glucose, a type of sugar. The dark reaction does not require light and can occur in the day or night¹².