Part of the photosynthesis process that puts carbon dioxide into the form of carbohydrates is the
calvin cycle
hill reaction
krebs cycle

The best answer is Calvin cycle.

The Calvin cycle is the main mechanism by which plants convert carbon dioxide into carbohydrates.  The Calvin cycle occurs in three major stages namely the carboxylation phase, reduction phase and regeneration phase in that order.

It is in the carboxylation phase that with the help of an enzyme called RuBisCo that carbon dioxide is added to a sugar called  ribulose  to form a 6-carbon intermediate which is then converted to 3PGA (3-phosphoglycerate)

3PGA goes through the remaining stages to finally  form G3P (glyceraldehyde3 phosphate) which is then used to make carbohydrates essential to the plant  such as sucrose, glucose, starch  and cellulose.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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