Benthoic animals are those, which
are deep dweller in sea
are floating (free) organisms
are submerged in sea
float on the sea surface
A.
are deep dweller in sea
The benthic zone is the ecological region at the very bottom of the sea. It includes the sediment surface and some sub-surface layers. The term 'benthic' was originally used for those animals which live on sea bottom.
The formation of canal system in sponges is due to
reproduction
porous walls
folding of inner walls
gastro- vascular system
Select the option that correctly matches characteristic features with the group of three animals.
Skeleton ofspicules - Sycon, Adamsia, Spongilla
Excretion by flame cells - Taenia, Fasciola, Ancylostoma
Mouth contains radula - Dentalium, Octopus, Ophiura
Jointed appendages - Limulus, Apis, Laccifer
Assertion: The nymph of a cockroach undergoes moulting several times.
Reason: There is gradual metamorphosis in cockroach.
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.
Some salient features and phyla of organisms are given below. Select the option which shows correct combination of organism, its phylum and salient features.
Which of the following waste products in grasshopper is not excreted and is used in other metabolic activities
Carbon dioxide
Water
Uric acid
Faeces
Assertion: Cephalisation is advantageous to an animal.
Reason: Cephalisation improves the appearance of an 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.
Cochineal insects have proved very useful for
rodents control
Parthenium control
cactus prevention
Eicchornia prevention
