Define ureotelism. Name the excretory organs of earthworm.

Explanation

### Step-by-Step Text Solution:

**Step 1: Define Ureotelism**
- Ureotelism is a biological process in which organisms excrete nitrogenous waste primarily in the form of urea. This method of excretion is advantageous because urea is less toxic compared to other nitrogenous wastes, such as ammonia, and is more soluble in water. As a result, organisms that exhibit ureotelism conserve water effectively, as they do not need to excrete large volumes of water along with their waste.

**Step 2: Identify the Excretory Organs of Earthworm**
- Earthworms belong to the phylum Annelida, which consists of segmented worms. The excretory organs of earthworms are called nephridia. Nephridia are present in each segment of the earthworm's body and function to remove waste products from the coelomic fluid and expel them outside the body. This segmentation allows for redundancy; if an earthworm is cut, the remaining segments can still function due to the presence of nephridia in each segment.

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