Answer:
D. A mutation causing uncontrolled cell division
Explanation:
Cell division is controlled by various mechanisms. Any mutations in the genes regulating the cell division lead to uncontrolled cell division. Loss of control over the process of cell division leads to the formation of tumors.
These tumors may cause cancer if they are transformed into malignant tumors. Hence, a mutation that causes loss of control over cell division is harmful.
I believe is the thermoreceptors present in the skin as well as part of the brain called hypothalamus.