What is the fluid-filled space that contains enzymes for light-independent reactions called?

The stroma is the fluid-filled space found inside chloroplasts that plays a crucial role in the process of photosynthesis, specifically in the light-independent reactions, also known as the Calvin cycle. It contains enzymes necessary for converting carbon dioxide and other compounds into glucose. This area of the chloroplast is also rich in starch granules and contains the chloroplast's DNA and ribosomes, supporting its functions.

In contrast, the thylakoid refers to the membrane-bound structures where the light-dependent reactions take place, not the light-independent reactions. The matrix generally describes the fluid within mitochondria, which is involved in cellular respiration rather than photosynthesis. Grana are stacks of thylakoids that enhance the efficiency of light absorption, again relating more to the light-dependent reactions. Thus, the stroma is the correct term for the space where the light-independent reactions occur, making it integral to the overall process of photosynthesis.