Final answer:
The complete statement with the blank filled in is: Skeletal muscle cells have many, and mature red blood cells have none at all; but nearly all other cells of the body have a single nucleus. Skeletal muscle cells have multiple nuclei, whereas mature red blood cells do not contain a nucleus at all, which differentiates them from most other body cells that have a single nucleus.
"the correct option is approximately option A"
Step-by-step explanation:
The subject of this question is the number of nuclei present in different types of muscle cells and in mature red blood cells. When filling in the blank in the given statement, the correct answer is: (a) nucleus.
Skeletal muscle cells are unique compared to the other muscle cells in the body because they have multiple nuclei, making them multinucleated. During their development, many precursor cells merge together, each contributing its nucleus to the mature skeletal muscle cell. Hence, the mature muscle fiber retains all the nuclei from the fused cells. In contrast, mature red blood cells, also known as erythrocytes, lack a nucleus entirely.
This allows more room for hemoglobin, which is crucial for oxygen transport throughout the body. All other cells in the body typically possess a single nucleus, which is the control center of the cell where genetic material is stored.