The mechanisms that regulate when a cell divides fail to work in cancer patients.
a. true
b. false

The question says, the mechanism that regulate when a cell divide fail to work in cancer patients. The statement is true. Cell growth and development are strictly controlled in the human system by specific mechanisms. The control system places restriction on cell growth and facilitate cell division and cell destruction at appropriate time. When the control system detect an abnormal cell, they destroy it quickly. In cancer patients, the control system mechanism is no longer acting, therefore cells continue to grow without any restriction, this result in tumors which is the hallmark of cancer.