Photosynthesis is an endothermic chemical reaction that forms sugars from carbon dioxide, water, and the sun's energy. which of the following must be true of photosynthesis? the reaction can take place only if energy is added. the reactants are oxidized. the photosynthesis reaction produces ions. the molecular bonds in carbon dioxide are very weak.

The reaction can take place only if energy is added.

Explanation:

Exothermic processes are those processes in which heat is released and endothermic processes are those processes in which heat is absorbed.

Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.

Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy in the form of glucose which is used a s a source of energy by many organisms.

Thus photosyynthesis reaction can take place only if energy is added.

the volume of fluid displaced would equal the volume of the gas. use a gas syringe - this is a laboratory instrument that can be used to withdraw a certain volume of gas from a closed system or to measure the volume of gas from a chemical reaction.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.