The digested food in small intestine is absorbed into blood vessels in the walls of small intestine through millions of tiny finger-like outgrowths called W. The undigested and unabsorbed food from the small intestine enters into another organ X. The organ X absorbs most of the water from the undigested waste food material making ir semi-solid. This semi-solid waste is stored in Part Y of organ X for some time. It is passed out from the body through part Z in the form of faeces.
What is X?

Explanation

### Step-by-Step Solution:

1. **Identify the Function of the Small Intestine**: The small intestine is where most of the digestion and absorption of nutrients occurs. It has tiny finger-like projections that help in this process.

2. **Name the Finger-like Projections**: These tiny finger-like outgrowths in the walls of the small intestine are called **villi**. They increase the surface area for absorption.

3. **Understand What Happens to Undigested Food**: After the digestion and absorption in the small intestine, any undigested and unabsorbed food material moves into another organ.

4. **Identify Organ X**: The organ that receives the undigested and unabsorbed food from the small intestine is the **large intestine**.

5. **Function of the Large Intestine**: The large intestine absorbs most of the water from the undigested waste food material, transforming it into a semi-solid form.

6. **Identify Part Y**: The semi-solid waste is stored in a part of the large intestine called the **rectum**.

7. **Identify Part Z**: Finally, the waste is expelled from the body through an opening called the **anus**.

### Final Answer:
**X is the large intestine.**