What are malignant tumors?

Malignant tumors grow by invading nearby cells and spread to other parts of the body through a process called metastasis. Cells break off the tumor, enter the bloodstream or lymphatic system, and spread to another area, infecting additional tissue. This is how a tumor which starts in one part of the body, such as the breast or prostate, can spread to another type of tissue, such as the bones.

His goal is  achievable, realistic, measurable, and time-based. : )

Answera tightly sealed house with an unvented water heater;