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Asymmetry in gastropoda is due to torsion.

(b) Fluctuates with surrounding temperature

(b) Platypus

Protonephridia are the excretory structures present in Planaria.

The central cavity of the sponges is called spongocoel.

Ostia: 

• The minute pores lining the body wall of sponges are called ostia. 
• Water enters through ostia.

Osculum: 

• The large opening in sponges is called osculum. 
• Water goes out through osculum.

The members of subphyla – Urochordata and Cephalochordata are collectively called protochordates.

Comb plates are present in ctenophores.

Ommatidia are the units that constitute the compound eyes in Insects.

(c) Millipede

Crocodiles have a four chambered heart.

Cellular, cell- tissue, tissue-organ are the grades of organization in animals.

Kingdom Animalia, class-11, 

The animals are classified as acoelomates, pseudocoelomates, and coelomates based on body cavity.

Animals show three fundamental body plans as follows: 

1. Cell aggregate body plan. 

2. Blind sac body plan, 

3. Tube within tube body plan. 

1. Cell aggregate body plan: 

a. In this body plan, cells do not form tissues or organs. 

b. Differentiation and division of labour among the cells is minimal. 

c. Members of phylum Porifera show cell aggregate body plan. 

2. Blind sac body plan: 

a. In this body plan, the body is sac-like with a single opening. Digestion is carried out in this sac-like structure. 

b. The food is ingested and egested through the same opening. 

c. Members of phylum Cnidaria show a blind sac body plan.

3. Tube within tube body plan: 

a. Digestive system is present in tube-like body cavity. 

b. Mouth and anus are present at two separate ends of the digestive system. 

c. Phylum Annelida onwards all phyla show tube within tube body plan.

Fig i. represents asymmetry 

Fig ii. represents radial symmetry 

Fig iii. represents bilateral symmetry

Mollusca (Mollis: Soft) is the second largest phylum. 

Unique features of phylum Mollusca: 

1. Habitat: They are aquatic or seen in marshy places. Few of them are terrestrial. 

2. Forms: Molluscs are either free-living or sedentary. 

3. Body plan: These are soft bodied and show tube within a tube type of body plan.

4. Body symmetry: Most of the Molluscs show bilateral symmetry but few are asymmetrical due to torsion (twisting). 

5. Body division: Body consists of head, foot and visceral mass. Visceral mass is enclosed in thick, muscular fold of body wall called mantle. Mantle secretes a hardcalcareous shell, that may be external or internal or absent. Muscular foot is present ventrally. 

6. Digestive system: Digestive system is well-developed and complete with anterior mouth and posterior anus. Buccal cavity has a rasping organ called radula (helps in feeding), which is provided with transverse rows of teeth. 

7. Respiration: In aquatic forms, numerous feather-like gills called ctenidia, help in aquatic respiration. Terrestrial forms may show the presence of lungs. 

8. Circulatory system: Circulatory system is of open type (except in Sepia, where it is of the closed type). Blood contains a copper-containing blue coloured respiratory pigment called haemocyanin. 

9. Excretion: Excretion occurs by kidney like structures, also called ‘Organ of Bojanus’. 

10. Sense organs: Sense organs such as eyes for vision, tentacles for tactile sensation and osphradia for testing purity of water is present.

11. Sexual reproduction: Sexes are usually separate. Animals of this phylum are mostly oviparous and the development is direct or indirect. 

12. e.g. Pila, Spisula (Bivalve), Octopus (devil fish), Sepia (cuttle fish), Chaetopleura (Chiton), Pinctada (Pearl oyster), Loligo (Squid), Aplysia (Sea hare), Dentalium (Tusk shell).

The symmetry in which the animals have two planes of symmetry, longitudinal and sagittal axis and longitudinal and transverse axis is biradial symmetry, e.g. Ctenophores.

The animals which excrete ammonia dissolved in water are called ammonotelic animals. More water is spent, e.g. fishes.

The animals which change their body temperature according to the environment are called poikilothermic.

The migration of marine fishes to fresh water body like rivers for spawning is known as anadromous migration.

The chordates which have notochord only in the tail region of the larval stage are called urochordates e.g. Ascidian.

Cnidoblasts: Presence of cnidoblasts or stinging cells are present on the tentacles for anchorage, offence and defence.

Distinguishing features of Tunicata or Urochordata: 

1. Habitat: They are exclusively marine.

2. Body covering: Soft body is covered by ‘test’ or ‘tunic’ which is made up of tunicine. 

3. Notochord: Notochord is present only in the tail of the larva and is lost during metamorphosis. Hence, the name Urochordata. 

4. Respiration: Pharynx with many gill slits for respiration. 

5. Circulation: Closed circulatory system is present.

6. Reproduction: Development is indirect, e. g. Herdmania, Salpa, Doliolum, Ascidia.

Exoskeleton: Exoskeleton is made up of feathers. Scales are present on hind-limbs. Skin is thin, dry and non-glandular except oil gland at the base of tail (uropygial gland).

Salient features of phylum Echinodermata (Echinus – spines, derma – skin) 

1. Habitat: These are exclusively marine. 

2. Forms: Members of this phylum are solitary, sedentary or free-living and gregarious, benthic. 

3. Body symmetry: These animals are radially symmetrical with pentamerous symmetry.

4. Shape: Members of Echinodermata are spherical, elongated or star-shaped. 

5. Body: The endoskeleton is made up of calcareous ossicles. Spines are formed on the body. Hence, they are known as echinoderms. The body has two sides oral and aboral and lacks definite divisions. Mouth is ventrally present on oral surface and anus on aboral surface. 

6. Water vascular system: Presence of water vascular system is the peculiar character of echinoderms. The madrepOrite is the opening of water vascular system through which water enters. Water vascular system is useful in locomotion, food capturing, respiration. 

7. Digestion: Digestive system is complete. 

8. Respiration: Peristomial gills, papillae, respiratory tree, etc. are used for respiration.

9. Circulatory and excretory systems: Absent in echinoderms.

10. Nervous system: Nervous system is simple with a nerve ring around the mouth and radial nerves in arms. 

11. Reproduction and development: Sexes are separate (sometimes bisexual). Fertilization is external. 

12. Development is indirect, i.e. through larval stages. They show high power of regeneration. 

e.g. Sea lily (Antedon), Sea star (Asterias), Sea cucumber (Cucumaria), Brittle star (Ophiothrix), Sea urchin (Echinus).

Balanoglossus belongs to phylum Hemiehordata.

For Explanation:

1. Hemiehordata was earlier considered as sub phylum of Chordata because the buccal diverticulum was considered as notochord. It is now placed as a separate phylum under Non-Chordata. 

2. It possesses certain characteristics of both Chordates and Non-chordates. 

3. Absence of notochord worm-like body, heart located on the dorsal side are the Non-chordate like characteristics seen in Hemiehordata. 

4. Presence of nerve chord, pharyngeal gill slits are some of the Chordate-like characters seen in Hemiehordata. Hence, Hemiehordata is considered as a connecting link between Nonchordata and Chordata.

The organism in the given picture is Comb jelly (Red midwater Comb jelly) and it belongs to phylum Ctenophora.

1. The organism in the given picture is Eel and it belongs to phylum Chordata.

2. The given organism in the given picture is Dolphin and it belongs to class Mammalia.

3. The given organism is Snake and it belongs to class Reptilia

4. The given organism is Sea urchin and belongs to phylum Echinodermata.

5. The given organism is flying lizard and belongs to class Reptilia.

6. The organism is Herdmania and belongs to Phylum Chordata (Subphylum Urochordata).

7. The organism in the given picture is Nautilus and it belongs to phylum Mollusca.

8. The organism in the given picture is Amphioxus and it belongs to Phylum Chordata (Subphylum Cephalochordata).

Schizocoelomates: In schizocoelometes, the body cavity is formed by splitting of mesoderm, e.g. Annelids, arthropods and molluscs.

Enterocoelomates: In enterocoelomates, the body cavity is formed from the mesodermal pouches of archenteron. e.g. Echinoderms, hemichordates and chordates.

Correct Answer is: (d) liver

Correct Answer is: (d) lamprey

(a) blue whale

(a) amphibian

Correct Answer is: (c) tortoise

Ichthyophis is a limbless amphibian.

The feather like gills of molluscs are called ctenidia.

The ability to regrow the lost parts is called regeneration, e.g. Planaria.

Ospharidium are helpful to test the purity of water.

Animals active at night are called nocturnal.

The body of annelids are divided into segments. This phenomenon is known as metamerism.

Haemocyanin, a copper containing pigment.

Haemoglobin and chlorocruorin.

(b) Arachnids

Correct Answer is: (a) Insects

(d) All of these

(b) Flame cells

(d) None of these

(d) Liver fluke

(d) Liver fluke