What are malignant tumors?
1. tumors that grow slowly and do not spread from their original site
2. tumors that grow fast and spread to neighboring tissues
3. tumors that start in blood-forming tissue and produce abnormal blood cells

The correct answer is choice 2. tumors that grow fast and spreading to neighboring tissues. Malignant tumors or cancerous tumors are tumors that grows and multiply to become cancer overtime. This tumors are due to the high unstable abnormal cells that travels in the blood stream.

Malignant tumors are: 2. tumors that grow fast and spread to neighboring tissues This type of tumor is considered really dangerous because the tumor could potentiallly pressed a crucial nerve endings that could cause someone to lose functions of some parts of their body if they're not treated as soon as possible.