Question

which order of events is correct?
stem cells → zygote → cell differentiation
zygote → cell differentiation → mitosis
zygote → stem cells → cell differentiation
mitosis → cell differentiation → stem cells

Explanation:

To determine the correct order, we analyze the biological processes: A zygote is the initial cell formed by fertilization. It undergoes mitosis to form stem cells (which are undifferentiated cells). Then, these stem cells undergo cell differentiation to form specialized cells. Let's check each option:

• First option: Stem cells come after zygote, so this order is wrong.
• Second option: Mitosis occurs before cell differentiation (as zygote divides by mitosis to form cells that then differentiate), so this is wrong.
• Third option: Zygote forms first, then gives rise to stem cells (through mitosis), and then stem cells undergo differentiation. This matches the biological sequence.
• Fourth option: The order of mitosis, cell differentiation, and stem cells is incorrect as stem cells are involved earlier in the process.

Answer:

C. zygote $
ightarrow$ stem cells $
ightarrow$ cell differentiation (assuming the third option is labeled as C; if the original options had labels like A, B, C, D, adjust the label accordingly. Based on the given options, the correct one is "zygote $
ightarrow$ stem cells $
ightarrow$ cell differentiation")