Which of the following occurs during the embryonic stage of development?

• A. Aging and senescence of cells
• B. Formation of mature gametes
• C. Initiation of meiosis in somatic cells
• D. Rapid cell division and differentiation of tissues

Answer: (D)

Verified step by step guidance

1. Understand the embryonic stage of development: This stage occurs after fertilization and involves the early formation of the organism. It is characterized by rapid cell division (mitosis) and the differentiation of cells into specialized tissues and organs.
2. Eliminate incorrect options: Aging and senescence of cells occur later in life, not during the embryonic stage. Formation of mature gametes happens during reproductive maturity, not in the embryonic stage. Initiation of meiosis occurs in germ cells, not somatic cells, and typically happens during gametogenesis, not embryonic development.
3. Focus on the correct process: During the embryonic stage, the zygote undergoes rapid mitotic divisions (cleavage) to form a multicellular structure called a blastula. This is followed by gastrulation, where cells begin to differentiate into distinct tissue layers (ectoderm, mesoderm, and endoderm).
4. Explain differentiation: Differentiation is the process by which unspecialized cells (stem cells) develop into specialized cells with specific functions, such as muscle cells, nerve cells, or blood cells. This is a key feature of the embryonic stage.
5. Conclude with the correct answer: The embryonic stage is defined by rapid cell division and differentiation of tissues, which is essential for the formation of the organism's body plan and organ systems.