The answer is to this question is A
The answer is carbon, hoped this helps you!
Answer:
Does not take up the stain.
Explanation:
Negative staining refers to the process wherein the unstained specimen is visualized under the darkly stained background.
One of the examples is capsule staining wherein the capsulated cells are stained with India ink or nigrosin dyes. The particles of these dyes stain the background blue-black but cannot enter the capsule.
Hence, the light-colored capsulated cells are visualized in the midst of the blue-black background.
Teperature
Ph level
Substrate concentration
Not sure if these are physical but hope it helped.
