**Explanation:**

**Vitamin K** is the vitamin that helps in the clotting of blood. It is an essential nutrient that plays a key role in the coagulation process, which helps to prevent excessive bleeding when a blood vessel is injured.

**Clotting Process:**

When a blood vessel is damaged, the body initiates a series of reactions known as the clotting cascade to form a blood clot. This process involves the activation of various clotting factors, which ultimately leads to the formation of fibrin, a protein that forms a mesh-like network to trap blood cells and platelets, creating a clot.

**Role of Vitamin K:**

Vitamin K plays a crucial role in the clotting process by activating certain clotting factors. It is essential for the production of prothrombin, a protein that is converted into thrombin, an enzyme that converts fibrinogen into fibrin. Fibrin forms the structural basis of a blood clot.

**Types of Vitamin K:**

There are two main forms of vitamin K - vitamin K1 (phylloquinone) and vitamin K2 (menaquinone).

- **Vitamin K1:** It is found in green leafy vegetables like spinach, kale, and broccoli. It is the primary form of vitamin K found in the diet.

- **Vitamin K2:** It is produced by bacteria in the gut and is also found in certain fermented foods like cheese and natto (a traditional Japanese food made from fermented soybeans).

**Absorption and Function:**

Vitamin K is a fat-soluble vitamin, which means it requires dietary fat for absorption. It is absorbed in the small intestine along with dietary fat and is then transported to the liver. In the liver, vitamin K is used to produce clotting factors and is also transported to other tissues in the body where it is required.

**Deficiency and Excess:**

- **Deficiency:** A deficiency of vitamin K can lead to impaired blood clotting and an increased risk of bleeding. Symptoms of deficiency include easy bruising, nosebleeds, and excessive bleeding from wounds.

- **Excess:** Excessive intake of vitamin K is rare and usually not a concern, as the body has a limited capacity to store this vitamin. However, extremely high doses of vitamin K supplements can interfere with the effects of certain blood-thinning medications.

In conclusion, vitamin K is the essential vitamin that helps in the clotting of blood by activating clotting factors and promoting the formation of fibrin. Its deficiency can lead to bleeding disorders, while excessive intake can interfere with certain medications.