This set of Zoology Multiple Choice Questions and Answers focuses on “Structural Organisation in Animals – Earthworm – 2”.
1. The body wall of the earthworm is externally covered by ______
Explanation: The body wall of the earthworm is externally covered by the cuticle. It is thin and non-cellular. The epidermis lies below the cuticle. It also contains two layers of muscles and an inner coelomic epithelium.
2. The epidermis of earthworm is made of ______
a) squamous epithelial cells
b) cuboidal epithelial cells
c) columnar epithelial cells
d) multi-layered squamous epithelial cells
Explanation: The epidermis is made of columnar epithelial cells. They are present in a single layer. The epidermis lies below the cuticle. There are two layers of muscles present below the epidermis. Human skin is made of squamous epithelium.
3. The buccal cavity of the earthworm leads to the _____
Explanation: The buccal cavity is present from the 1st to 3rd segment. It is the mouth part of the body of the earthworm. The buccal cavity opens up into the pharynx. The pharynx is made of muscular tissue.
4. Identify the correct pathway of food ingested by an earthworm.
Explanation: Food is ingested by the earthworm through the mouth. The mouth part opens up into the muscular pharynx. This is followed by a narrow esophagus followed by the gizzard where food is broken down by the process of grinding.
5. What is the function of gizzard in earthworm?
a) Secretion of digestive enzymes
b) Grinding soil particles and leaves
c) Absorption of water
d) It is a respiratory structure
Explanation: The gizzard has the principal role of grinding soil particles and decaying leaves. It does not secrete digestive enzymes nor does it play a role in water absorption. It is not a respiratory structure and only helps in the mechanical breakdown of food.
6. Where are the calciferous glands of the earthworm present?
Explanation: The calciferous glands of the earthworm are present in the stomach. The food of the earthworm contains soil particles and humus. The calciferous glands neutralize the humic acid which is present in the humus.
7. Which segments of the earthworm contain the stomach?
a) 9th to 14th
b) 23rd to 25th
c) 16th to 18th
d) 5th to 8th
Explanation: The stomach of the earthworm extends from the 9th to 14th segments. It is present after the gizzard, where the ingested food is mechanically grinded before being passed through to the stomach.
8. Which segment of the earthworm contains the intestinal caecum?
Explanation: The 26th segment of the body of the earthworm contains intestinal caeca. It projects out from the wall of the intestine. The intestine of the earthworm starts at the 15th segment and continues till the last segment.
9. What is the function of typhlosole in earthworm?
a) Mechanical breakdown of food
b) Secretes digestive enzymes
c) Increases the surface area for absorption
d) Excretes waste products
Explanation: Typhlosole is present in the intestine after the 26th segment. It arises from the median fold of the dorsal wall. It increases the surface area of absorption of nutrients from the digested food material.
10. Open blood vascular system is present in Pheretima.
Explanation: Pheretima has a closed blood vascular system. This implies that its blood is confined to the components of the vascular system only. The components of this vascular system are heart, blood vessels and capillaries. In closed type of vascular system, the circulating blood travels in one direction only.
11. Which segments of the earthworm contain the blood glands?
a) 9th to 12th
b) 16th to 18th
c) 23rd to 25th
d) 4th to 6th
Explanation: The 4th, 5th and 6th segments of the body of the earthworm contain the blood glands. The function of these glands is to produce blood cells and hemoglobin. These components of blood are dissolved in the blood plasma.
12. Respiratory exchange in earthworms takes place through ______
c) body surface
Explanation: Respiratory exchange in earthworms takes place via the body surface. Since earthworm is an annelid, it lacks gills and lungs. The mouth of the earthworm is responsible for uptake of food only.
13. What is the excretory organ in earthworm known as?
Explanation: Nephridium is the excretory organ in earthworm. Nephridia occur as coiled tubules arranged segmentally. Typhlosole and gizzard are involved in digestion of food while setae help in locomotion.
14. Which of the following is not a type of nephridia present in earthworm?
Explanation: The nephridia in earthworm are of three types – septal nephridia, integumentary nephridia and pharyngeal nephridia. All three types are similar in structure. Intestinal nephridia is not present.
15. Which of the following is not true about nephridia in earthworm?
a) They are excretory organs
b) They do not regulate the composition of body fluids
c) They are of three types
d) They regulate the volume of body fluids
Explanation: Nephridia regulate both the volume as well as the composition of body fluids. They are the excretory organs of the earthworm. They are of three types – septal, integumentary and pharyngeal.
Sanfoundry Global Education & Learning Series – Biology – Class 11.
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