Which of the following is neurotoxic -a) Sea snakeb) Russel viperc) Kraitd) Cobrae) Pit viper

**Core Concept**
Venomous snakes possess toxins that can cause various systemic effects, including neurotoxicity, cardiotoxicity, and hemorrhagic necrosis. Neurotoxins target the nervous system, disrupting normal function and leading to respiratory failure, paralysis, and even death.

**Why the Correct Answer is Right**
Neurotoxins are proteins that bind to nicotinic acetylcholine receptors (nAChRs) on the neuromuscular junction, blocking acetylcholine from binding and preventing muscle contraction. This results in flaccid paralysis, respiratory failure, and eventually, death if left untreated. Sea snakes (Hydrophiinae) are known for their potent neurotoxins, which are directed at the nicotinic acetylcholine receptors.

**Why Each Wrong Option is Incorrect**
**Option A:** Sea snakes are indeed neurotoxic, as explained above.
**Option B:** Russell's viper (Daboia russelii) is primarily a hemotoxic snake, causing renal failure, hemorrhage, and necrosis through its venom.
**Option C:** Kraits (Bungarus spp.) are also primarily hemotoxic, causing renal failure, muscle necrosis, and hemorrhage through their venom.
**Option D:** Cobras (Naja spp.) are primarily neurotoxic, but their venom is more complex, containing both neurotoxins and hemotoxins.
**Option E:** Pit vipers (Crotalinae) are primarily hemotoxic, causing renal failure, hemorrhage, and necrosis through their venom.

**Clinical Pearl / High-Yield Fact**
When treating snakebites, it's essential to identify the species and administer appropriate antivenom. In cases of neurotoxic envenoming, antivenom can help neutralize the toxins and prevent respiratory failure.

**Correct Answer: A. Sea snake**