**Core Concept**
The venom of sea snakes contains a unique combination of enzymes and peptides that target various physiological systems, making them a significant concern for human health. Specifically, the venom of these snakes is predominantly composed of **neurotoxins**, which can cause respiratory failure and cardiac arrest if left untreated.

**Why the Correct Answer is Right**
The venom of sea snakes is primarily composed of **post-synaptic neurotoxins**, which act by binding to the nicotinic acetylcholine receptor (nAChR) at the neuromuscular junction. This binding causes a persistent depolarization of the muscle cell membrane, leading to an accumulation of acetylcholine and subsequent muscle paralysis. The **phospholipase A2 (PLA2)** enzymes present in the venom also contribute to the toxic effects by disrupting cell membranes and promoting inflammation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as the venom of sea snakes is not primarily composed of hemotoxins, which are more commonly associated with the venom of land snakes like cobras and vipers.
* **Option B:** This option is incorrect as the venom of sea snakes does not contain a significant amount of cardiotoxins, which are more commonly associated with the venom of some species of cobras and kraits.
* **Option C:** This option is incorrect as the venom of sea snakes is not primarily composed of cytotoxins, which are more commonly associated with the venom of some species of snakes like the inland taipan.

**Clinical Pearl / High-Yield Fact**
The venom of sea snakes is highly specific to the nicotinic acetylcholine receptor, making them a valuable tool for researchers studying the structure and function of this receptor. In fact, the venom of the Indian sea snake has been used to develop a specific antivenom that is highly effective against sea snake bites.

**Correct Answer:** D.