Based on toxicological characteristics, which form of mercury is important?
A.Elemental
B.Inorganic
C.Organic
D.All of the above

Hint: Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants. The substances that are assessed by toxicologists include environmental agents and chemical compounds found in nature, as well as pharmaceutical compounds that are synthesized for medical use by humans.

Complete answer:
Mercury is available in three forms to us namely, elemental mercury, organic mercury compounds primarily as methylmercury and inorganic mercury compounds primarily as mercuric chloride.
All three of these forms affect the health of human beings. Short-term exposure to high-levels of elemental mercury in humans affects the central nervous system. These effects include tremors, mood changes and slowed sensory and motor nerve function.
Short term exposure to inorganic mercury by the oral route may result in effects such as nausea, vomiting, and severe abdominal pain. The major effect from chronic exposure to inorganic mercury is kidney damage.
Acute exposure of humans to very high levels of methylmercury results in central nervous system effects such as blindness, deafness, and impaired level of consciousness.
Therefore, the correct option is D.

Note:
Factors that influence chemical toxicity include dosage, duration of exposure (acute/chronic), route of exposure, species, age, sex, and environment. Not all chemicals toxicity is harmful, some are used for the benefits of human beings. Toxicology is currently contributing to the field of Cancer research, since some toxins can be used as drugs for killing tumour cells. One prime example of this is Ribosome Inactivating Proteins, tested in the treatment of Leukaemia.