Among the different forms of electromagnetic radiation emitted by the sun, which form is absorbed by plants for photosynthesis?
Multiple Choice

Choice A rationale: CO2 is not the source of oxygen produced by a plant, but a reactant of 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 release any oxygen¹.

Choice B rationale: C6H12O6 is the chemical formula for glucose, which is the product of the dark reaction. Glucose is synthesized from CO2 and energy intermediates from the light reaction. Glucose does not produce any oxygen, but can be used by the plant for respiration or storage².

Choice C rationale: Glyceraldehyde-3-phosphate is an intermediate molecule in the dark reaction. It is formed from CO2 and energy intermediates from the light reaction, and then converted into glucose. Glyceraldehyde-3-phosphate does not produce any oxygen³.

Choice D rationale: H2O is the source of oxygen produced by a plant. In the light reaction, water is split by the energy from sunlight in photosystem II, releasing electrons, protons, and oxygen. The oxygen is either used for respiration or released into the air⁴.

Choice E rationale: O2 is the product of oxygen produced by a plant, not the source. O2 is released as a by-product of the splitting of water in photosystem II. O2 is either used for respiration or released into the air⁴.

Choice A reason: Benedict's test is a test for the presence of reducing sugars, such as glucose or maltose, in a solution. The test involves adding Benedict's reagent, which is a blue solution of copper (II) sulfate, sodium carbonate, and sodium citrate, to the solution and heating it in a water bath. If reducing sugars are present, they reduce the copper (II) ions to copper (I) ions, which form a red, orange, or green precipitate of copper (I) oxide. The color and amount of the precipitate indicate the concentration of reducing sugars in the solution. ¹

Choice B reason: Brown paper test is a test for the presence of lipids, such as fats or oils, in a solution. The test involves placing a drop of the solution on a piece of brown paper and letting it dry. If lipids are present, they leave a translucent spot on the paper, which can be seen by holding the paper against a light source. The test is based on the fact that lipids are nonpolar and do not dissolve in water, but can dissolve in organic solvents and stain the paper. ²

Choice C reason: Biuret test is a test for the presence of proteins or peptides in a solution. The test involves adding Biuret reagent, which is a blue solution of copper (II) sulfate and sodium hydroxide, to the solution. If proteins or peptides are present, they form a complex with the copper (II) ions, which changes the color of the solution to violet or pink. The test is based on the fact that proteins and peptides have peptide bonds, which have nitrogen atoms that can coordinate with the copper (II) ions. ³

Choice D reason: Iodine test is a test for the presence of starch in a solution. The test involves adding iodine solution, which is a brown solution of iodine and potassium iodide, to the solution. If starch is present, it forms a complex with the iodine molecules, which changes the color of the solution to blue-black. The test is based on the fact that starch is a polysaccharide that has a helical structure, which can trap the iodine molecules inside. ⁴

Choice E reason: Wendelspecht test is a fictional test that does not exist in reality. It is a made-up name that has no meaning or relevance to the topic of this question. Therefore, it cannot be a valid answer.