Answer:
The correct answer is a The calvin cycle requires products only produced when the photsystems are illuminated .It is often too cold at night for the reaction to take place.
Explanation:
It is true that the reactions of calvin cycle are not directly depends on light but depends on the products such as ATP and NADPH produced during light reaction.
ATP and NADPH is formed by the illumination of photosystems by sun light.So during night time there is no chance for the light dependent illumination of the photosystems.
As a result the ATP and NADPH are not formed during night .That"s why reactions of calvin cycle does not occur at night.
Arrangement of atoms or group of atoms in a three dimensional ordered pattern in a crystal is said to be a crystalline lattice. They are arranged in a specific pattern with high symmetry. The heating of the crystal at high temperature will result in the increase of vibrational kinetic energy of the atoms in the crystal and this will result in the breaking of lattice apart and due to the breaking of lattice apart the ions will flow freely.
Thus, the heating of a solid at high temperature will lead to the lattice breaks apart and ions will flow freely.