For the synthesis of one glucose molecule, the Calvin cycle operates for:

For the assimilation of one CO₂ molecule in C₃ plants, the energy required in the form of ATP and NADPH₂ is:

1. 2 ATP & 2 NADPH₂

2. 5 ATP & 3 NADPH₂

3. 3 ATP & 2 NADPH₂

4. 18 ATP & 12 NADPH₂

In C₃ plants, the first stable product of photosynthesis during the dark reaction is:

1. Oxaloacetic acid

2. 3-phosphoglyceric acid

3. Phosphoglyceraldehyde

4. Malic acid 

As compared to a $C_3$-plant, how many additional molecules of ATP are needed for net production of one molecule of hexose sugar by $C_4$-plants: