Which one of the following is the process involved in photosynthesis?

States that light energy is converted to chemical energy and water is split, indicating an energy conversion step in photosynthesis.

A student could combine this with basic biochemistry knowledge (light reactions produce ATP/NADPH and dark reactions fix CO2) to check whether the chemical energy formed is in forms usable as cellular free energy.

Defines photosynthesis as converting external substances into stored forms of energy (carbohydrates) that fulfil carbon and energy needs.

One could use the fact that stored carbohydrates can be metabolised to release energy (e.g., to make ATP) to assess whether stored potential energy is later turned into usable free energy.

Explains that ATP is the cellular energy currency and that energy released during respiration is used to synthesise ATP from ADP + Pi.

Combine with the idea that photosynthesis produces carbohydrates (stored energy) to infer that those carbs might be oxidised to release energy that forms ATP (cellular free energy).

Describes photosynthesis as conversion of light energy into carbohydrates and places primary producers at the base of energy flow in ecosystems.

Using a basic energy-flow concept (plants store light energy as chemical bonds), a student can trace whether that stored bond energy is later converted into forms usable by organisms (e.g., ATP).

Summarises inputs/outputs of photosynthesis and notes glucose serves as an instant energy source and is stored as starch.

A student could use this plus knowledge that 'free energy' in cells is often ATP to investigate whether glucose from photosynthesis is ultimately used to generate ATP.

States the core photosynthesis pattern: plants use carbon dioxide and water with sunlight and chlorophyll to produce glucose and oxygen (synthesis of food).

A student could contrast this with processes that consume glucose to see whether photosynthesis is a synthetic (build-up) or degradative (oxidative) process.

Lists the mechanistic steps of photosynthesis, including splitting water and reduction of carbon dioxide to carbohydrates (emphasizing reduction rather than oxidation).

A student can use the terms 'reduction of CO2' and 'splitting of water' to infer that photosynthesis involves electron gain (reduction) of carbon, opposite to oxidation of food.

Gives the respiration equation: glucose + oxygen → carbon dioxide + water + energy, showing that oxidation of glucose (food) produces CO2 and H2O.

By comparing this respiration equation with photosynthesis equations, a student can infer which process produces CO2/H2O (respiration) versus which consumes them (photosynthesis).

Describes photosynthesis as joining CO2 and water under light to produce energy-rich organic material (sugars) and release oxygen, framing it as a synthetic, energy-storing reaction.

A student could use this to reason that photosynthesis stores energy in organic molecules, so it is not the oxidative breakdown that releases CO2/H2O.

Shows examples of oxidation reactions (combustion) where carbon compounds react with O2 to yield CO2 and H2O, illustrating the general pattern of oxidation producing CO2/H2O and releasing energy.

A student may use this general rule (oxidation of organics → CO2 + H2O + energy) to identify that the release of CO2/H2O is characteristic of oxidative breakdown (like respiration/combustion), not of photosynthesis.

Describes the core steps of photosynthesis: water is split to yield hydrogen and oxygen, and CO2 is reduced to carbohydrates.

A student can use this to infer that oxygen is produced (from water) and CO2 is consumed during photosynthesis, so the reverse (taking in O2 and releasing CO2) would contradict this mechanism.

Explicitly states that photosynthesis requires carbon dioxide and that oxygen is released in the process.

Combine with the statement to note the mismatch: photosynthesis consumes CO2 and releases O2, so the claim of taking in O2 and giving out CO2 is likely inconsistent.

Summarizes that plants use CO2 and water to produce glucose and oxygen, and that stomata mediate exchange of O2 and CO2 during photosynthesis and respiration.

Use the stomatal exchange idea plus the listed reactants/products to reason that during daylight leaves mainly take in CO2 and emit O2, not the other way round.

Explains that during the day CO2 generated by respiration is used up for photosynthesis and oxygen release is the major event at this time; at night CO2 release dominates.

A student could extend this temporal pattern (day vs night) to test the claim by considering when plants would take in or release CO2/O2.

Notes that stomata enable large gas exchange for photosynthesis and that plants close stomata to prevent water loss when they do not need CO2.

Combine this with the known gas roles to infer that stomatal opening during photosynthesis facilitates CO2 uptake and O2 release rather than O2 uptake/CO2 release.