A failure of the cells in the ectoderm to differentiate correctly would most affect which of the following body systems?

A) epidermis of the skin
B) cardiovascular system
C) urinary system
D) digestive system
E) endocrine system

The ectoderm gives rise to the epidermis of the skin, as well as other structures such as hair, nails, and glands. Failure of differentiation in the ectoderm may result in abnormal development or function of these structures, leading to skin disorders or other related conditions. The cardiovascular, urinary, digestive, and endocrine systems are derived from different germ layers of the developing embryo, and would not be directly affected by a failure of ectodermal differentiation.