In plants,the uptake of $CO_2$ and the release of $O_2$ is a process called .........

How many molecules of water are needed by a green plant to produce one molecule of hexose or to reduce $6$ molecules of $CO_2$?

Match the following pairs:
$(A)$ Emerson effect $(a)$ $C_4$ cycle
$(B)$ Hill reaction $(b)$ Photolysis
$(C)$ Calvin cycle $(c)$ $C_3$ cycle
$(D)$ Hatch and Slack cycle $(d)$ Photosystem-$I$ and $II$

Assertion : Dark reaction occurs only at night in the stroma of chloroplast.
Reason : $CO_2$ fixation occurs only during $C_3$ cycle.

Assertion : Cyclic pathway of photosynthesis first appeared in some eubacterial species.
Reason : Oxygen started accumulating in the atmosphere after the non-cyclic pathway of photosynthesis evolved.

Assertion: Photosynthetically,$C_4$ plants are less efficient than $C_3$ plants.
Reason: The operation of the $C_4$ pathway requires the involvement of only bundle-sheath cells.