Question

Role of calciferous glands in stomach of earthworm is to
A. Neutralize the humic acid in the humus
B. Produce HCL
C. Emulsify fats
D. Increase absorptive area
E. Secretes slime

Answer 1

Hint: Earthworm is a terrestrial invertebrate that lives in the upper layer of moist soil. Earthworm is a reddish brown in color. They live in holes made by boring and swallowing the soil. For example: India earthworm is Pheretima and Lumbricus.

Complete answer:
- The body of earthworm is covered by a thin non-cellular shield below which is the layer of epidermis.
- Innermost layer of the earthworm is known as coelomic epithelium.
- The epidermis is made up of a single layer of columnar epithelial cells which contains secretory gland cells.
- The alimentary canal is a straight tube that runs between the first to last segment of the body.
- A mouth opens into the buccal cavity which leads into muscular pharynx.
- A small narrow tube known as esophagus opens into the muscular gizzard.
- It helps in crushing the soil particles and old and dead leaves.
- Stomach extends from 9-14 segments.
- The food of the earthworm is decaying leaves and organic matter mixed with soil.
- A calciferous gland which is present in the stomach, neutralizes the humic acid present in the humus.
- Intestine starts from the 15th segment onwards and continues till the last segment.

Hence, the correct answer is option (A).

Note: Typhlosole is the characteristic feature of intestine after 26 segments except the last 23 to 25 segments is presence of the internal median fold of dorsal wall. This increases the effective area of absorption in the intestine. The alimentary canal opens up into the small hole known as anus.