Final answer:
Clefting occurs during the embryonic stage of prenatal development, which spans from week 3 to week 8 after fertilization. This is a critical period for the formation of organ systems and facial features. The correct option is B.
Step-by-step explanation:
Clefting occurs during the embryonic stage of prenatal development. This stage runs from week 3 to week 8 after fertilization, during which all of the organ systems are structured in rudimentary form.
Clefting, which refers to the formation of a cleft or opening in the lip or palate, occurs during the embryonic stage of prenatal development.
This stage occurs from weeks 3-8 of gestation, during which the developing human is referred to as an embryo. It is characterized by cell division, migration, and differentiation of cells.
By the end of the embryonic period, organ systems are structured in rudimentary form. It is a critical period where the basic plan for all organ systems is established, including the development of facial features.
Genetic defects or harmful environmental exposures during the embryonic stage can lead to abnormalities such as clefting, so it is a particularly sensitive phase for the developing embryo. The correct option is B.