According to embryologist, embryo is termed till:
**Core Concept**
The development of a human being from fertilization to birth involves various stages of embryonic and fetal development. Embryologists use specific terms to describe these stages, which are crucial for understanding human development and congenital anomalies.
**Why the Correct Answer is Right**
The term "embryo" is used from fertilization until the end of the eighth week of gestation. During this period, the embryo undergoes significant morphological changes, including the formation of the three primary germ layers: ectoderm, mesoderm, and endoderm. The development of the embryo is characterized by the formation of the neural tube, heart, and major organs. After the eighth week, the term "fetus" is used, as the developing human being has developed beyond the embryonic stage and is now characterized by the presence of all major organs and body systems.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect as the term "embryo" is used before the eighth week of gestation, not after.
**Option B:** This is incorrect as the term "fetus" is used after the eighth week of gestation, not before.
**Option C:** This is incorrect as the term "embryo" is used until the end of the eighth week, not until the end of the second month.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the term "embryo" is used until the end of the eighth week, and any congenital anomalies or developmental issues that occur after this period should be described using the term "fetus."
**Correct Answer: C. 8 weeks**