However i did not pass the test. fix the sentence by adding a comma.

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different

Cells control gene expression at which steps