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

Choice A rationale: Distilled water is not a positive control, but a negative control for the iodine test. Distilled water is a pure solvent that does not contain any starch or other carbohydrates. It does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.

Choice B rationale: Olive oil is not a positive control, but a negative control for the iodine test. Olive oil is a lipid that does not contain any starch or other carbohydrates. It does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.

Choice C rationale: Albumin solution is not a positive control, but a negative control for the iodine test. Albumin is a protein that does not contain any starch or other carbohydrates. It does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.

Choice D rationale: Starch solution is a positive control for the iodine test. Starch is a polysaccharide that contains many glucose units linked by glycosidic bonds. Starch reacts with the iodine solution and produces a blue-black color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.

Choice E rationale: Glucose solution is not a positive control, but a negative control for the iodine test. Glucose is a monosaccharide that does not contain any glycosidic bonds. Glucose does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.

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.