Assertion : Torison can be seen in ctenidium.
Reason : Ctenidium acts as the respiratory organ.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Ctenidium is a monopectinate gill situated on the right side of the branchial chamber. It helps in respiration by beating of cilia, thus creating water current. It is innervated by nerves from the left pleural and supra-intestinal ganglia. It basically indicates that it is an organ of the left side but has shifted to the right side during development (torsion).
Torsion or twisting is a development of gastropods, which rotates the visceropallium anticlockwise through out 180° from its initial position, so that mantle cavity with its pallial complex, is brought in front of the body in adult.
During the life-cycle, Fasciola hepatica (liver fluke) infects its intermediate host and primary host at the following larval stages respectively
redia and miracidium
cercaria and redia
metacercaria and cercaria
miracidium and metacercaria.
Assertion: Blood in cockroach is colourless haemolymph with no respiratory pigment.
Reason: Respiration in cockroach occurs through diffusion in haemolymph.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Which one of the following features is common in silverfish, scorpion, dragonfly and prawn?
Two pairs of legs and segmented body
Living chitinous cuticle and two pairs of antennae
Jointed appendages and chitinous exoskeleton
Closed blood carcular system
Assertion: Cephalization is advantageous to an animal.
Reason: It improves the appearance of the animal
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Which one of the following pairs of the kind of cells and their secretion is correctly matched
| Oxyntic cells | a secretion with pH between 2.0 and 3.0 |
| Alpha cells of islets of Langerhans | secretion that decreases blood sugar level |
| Kupffer cells | a digestive enzyme that hydrolyses nucleic acids |
| Sebaceous glands | a secretion that evaporates for cooling |
All mammals without any exception are characterised by
viviparity and biconcave red blood cells
extra-abdominal testes and a four chambered heart
heterodont teeth and 12 pairs of cranial nerves
a muscular diaphragm and milk producing
glands.
Which one of the following animals is correctly matched with its one characteristic and the taxon
| Animal | Characteristic | Taxon |
| Millipede | Ventral nerve cord | Arachnida |
| Duckbill platypus | Oviparous | Mammalia |
| Silverfish | Pectoral and pelvic fin | Chordata |
| Sea anemone | Triploblastic | Cnidaria |
A lizard-like member of reptilia is sitting on a tree with its tail coiled around a twig. This animal could be
Hemidactylus showing sexual dimorphism
Varamus showing mimicry
garden lizard (Calotes) showing camouflage
Chamaeleon showing protective colouration
