Polychlorinated biphenyls (PCBs) are toxic to humans due to their ability to accumulate in the body over time, leading to various health issues. Here are the consequences of PCB exposure listed in the question and the correct option among them:
1. They weaken the immune system.
2. They cause liver damage.
3. They cause brain damage to children exposed in the womb.
4. They cause skin cancer.
The exception among these consequences is option "Od. They cause skin cancer." PCBs are not directly linked to causing skin cancer. Instead, they are known to impact the immune system, cause liver damage, and have neurotoxic effects, especially affecting brain development in children exposed in the womb.
Therefore, the correct answer to the question is: "Od. They cause skin cancer." This option is not a consequence of PCB toxicity to humans.
