A definite number of segments are found in

• slug

• earthworm

• leech

• tapeworm

The red colour of 'red sea' is due to which of the following blue-green algae?

• Chlamydomonas nivalis

• Anabaena

• Microcystis

• Trichodesmium

Some salient features and phyla of organisms are given below. Select the option which shows correct combination of organism, its phylum and salient features.

Cochineal insects have proved very useful for

• rodents control

• Parthenium control

• cactus prevention

• Eicchornia prevention

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

176.

The formation of canal system in sponges is due to

• reproduction

• porous walls

• folding of inner walls

• gastro- vascular system

Benthoic animals are those, which

• are deep dweller in sea

• are floating (free) organisms

• are submerged in sea

• float on the sea surface

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.

Retrogressive metamorphosis occurs in

• Hemichordata

• Cephalochordata

• Urochordata

• Vertebrata

Which of the following waste products in grasshopper is not excreted and is used in other metabolic activities

• Carbon dioxide

• Water

• Uric acid

• Faeces