Question

at a point during a cells development, it begins to differentiate. how does differentiation occur?
oa. certain genes are turned on and others are turned off; this action produces adult cells that are specialized
ob. the number of chromosomes in the cell is reduced by half; this action triggers the specialization of the cell.
oc. as a cell matures, genes that are not necessary to its function are ejected out of the cell through active transport.
od. a developing cells function is determined by the number of organelles that are contained in the cell.

Explanation:

Cell differentiation occurs when certain genes are activated (turned on) and others are inactivated (turned off). This gene - regulation process leads to the production of specialized adult cells.

• Option B is incorrect because the number of chromosomes in a somatic cell (non - reproductive cell) does not change during differentiation. Meiosis (a type of cell division) reduces the chromosome number by half, but that is for gamete (reproductive cell) formation, not for cell differentiation.
• Option C is incorrect. It is not about genes being ejected. Gene regulation (turning on and off) is the key, not physical ejection of genes.
• Option D is incorrect. The function of a cell is determined by gene expression, not just the number of organelles. Organelles are present based on the cell's function which is regulated by genes.

Answer:

A. Certain genes are turned on and others are turned off; this action produces adult cells that are specialized.