The failure of a tissue or organ to develop is referred to as B aplasia.
- Aplasia specifically means the absence or failure of an organ or tissue to develop.
- Hypoplasia refers to underdevelopment or incomplete development of a tissue or organ.
- Neoplasia refers to the abnormal and excessive growth of tissue, which can lead to tumors.
- Alopecia is the loss of hair.
Therefore, the correct answer is B aplasia.