In c 4 photosynthesis, carbon fixation takes place in the cells, and then is transferred as malic or aspartic acid to cells, where carbon dioxide is released for entry into the calvin cycle.

Carbon fixation occurs in mesophyll cells and then transferred as malate to the bundle-sheath cells, where carbon dioxide is released.

Explanation:

The Hatch–Slack pathway or the C₄ carbon fixation, is a type of photosynthetic process in some of the plants. C₄ carbon fixation refers to the production of four carbon molecule, first product of carbon fixation.

The process of carbon fixation initially occurs in the mesophyll cells, to form a simple four carbon organic molecule, oxaloacetate. The oxaloacetate is further converted to malate so that it can be transported to bundle-sheath cells.

In bundle sheath cells, break down of malate results in the release of carbon dioxide for entry into the Calvin cycle.