NCERT Class 11-Biology: Chapter –7 Structural Organization in Animals Part 5

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Question 11:

Correct the wrong statements among the following:

a. In earthworm, a single male genital pore is present.

b. Setae help in locomotion of earthworm.

c. Muscular layer in the body wall of earthworm is made up of only circular muscles.

d. Typhlosole is the part of intestine of earthworm.


a. Wrong statement.

Explanation: The given statement is incorrect. In earthworms, there is presence of a pair of male genital pore.

b. Correct statement.

Explanation: The earthworm uses the setae which anchors the front of its body and helps in the locomotion of the earthworm.

c. Wrong statement.

Explanation: The muscular layer in the body wall of the earthworm is not only made up of circular muscles but it also has longitudinal muscles. These muscles are integrated together in the earthworms for its locomotion and survival.

d. Correct statement.

Explanation: Typhlosole is a dorsal flap of the intestine in a earthworm. It runs from the 25th to 27th segment of the earthworm’s body.

Question 12:

Why nephridia in earthworm that are basically similar in structure classified into three types? Mention the names of each.


Nephridia in earthworms are useful for performing functions like excretion and osmoregulation. Although the nephridia in earthworms are similar in structure they are classified into different types based on their location. They are classified as:

1. Septal Nephridia: It is located in both sides of the intersegment septa from the 15th segment till the end which has about 80-100 Septal nephridia on a particular segment. They open into the intestines of the earthworm.

2. Pharyngeal Nephridia: It is located in the 4th, 5th and 6th segment of the earthworm. The 6th segment nephridia open into the buccal cavity while the 4th and 5th nephridia segment opens into the pharynx. The excretory matter is carried into the gut by these ducts.

3. Integumentary Nephridia: It is located in the body wall i.e., the integument of the earthworm. It is present on every segment of the earthworm and it is highly abundant in the Clitellar region. These nephridia discharge the excretory products directly outside the body of the earthworm.

Question 13:

Common name of some animals are given in Column A, write their scientific name in Column B.

Common name of some animals

Column A

Column B











Column AColumn B

a. Tiger Panthera Tigris.

b. Peacock Pavocristatus.

c. Housefly Musca domestica.

Question 14:

Complete the following statement:

a. In Cockroach grinding of food particle is performed by ____________

b. Malpighian tubules help in removal of ___________________________

c. Hind gut of Cockroach is differentiated into ______________________

d. In Cockroach blood vessels open into spaces called ______________


a. In cockroach grinding of food particle is performed by gizzard.

Explanation: Gizzard in the cockroaches is defined as a muscular stomach which has teeth like structures which helps in grinding the food into smaller and simpler particles.

b. Malpighian tubules help in removal of Nitrogenous excretory products.

Explanation: The Malpighian tubules are responsible for removal of nitrogenous waste in cockroaches and also in osmoregulation. The Malpighian tubules absorb the nitrogenous waste products produced by the cockroach and then covert it to simpler uric acid for excretion.

c. Hind gut of cockroach is differentiated into ileum, colon and rectum.

Explanation: Hind gut has the three differentiated parts - ileum, colon and rectum which are mainly used for the reabsorption of nutrients.

d. In cockroach blood vessels open into spaces called Haemocoel.

Explanation: The blood vessels open into spaces known as the haemocoel which are further divided into sinuses.