Final answer:
Neoplasia is the term for the new and abnormal development of cells which may form benign or malignant tumors, with malignant tumors being capable of spreading and turning cancerous.
Step-by-step explanation:
The new and abnormal development of cells that may be either benign or malignant is called neoplasia. Neoplasia is characterized by the formation of new, abnormal tissue growth known as a neoplasm, which can result in a benign tumor or a malignant tumor. Benign tumors are non-cancerous and typically do not spread beyond their site of origin. In contrast, malignant tumors are cancerous and can invade surrounding tissues and metastasize to distant body parts.