Which of the following describes a malignant tumor?

A malignant tumor is characterized by its ability to invade and destroy nearby tissues, making option B the correct answer. This invasive behavior arises from the uncontrolled growth of cancerous cells which can penetrate surrounding tissues, disrupt normal tissue function, and potentially spread (metastasize) to other parts of the body.

In contrast, non-harmful tumors are generally classified as benign and do not possess the aggressive traits seen in malignant tumors, which is why option A is not accurate. Tumors that can be easily removed, typically benign ones, do not exhibit the same destructive tendencies that define malignant tumors, making option C inappropriate. Additionally, a benign tumor, by definition, does not spread throughout the body and remains localized, thus option D does not apply to the definition of malignant tumors. Understanding these characteristics is essential for recognizing the differences between benign and malignant conditions in clinical settings.