Available Answers

1. 1.

   Fill in the blanks.

   1. ____________ do not have a backbone, while ___________ have it.
   2. Cnidarians have ____________ symmetrical body.
   3. ___________ and ___________ live in the intestines of human beings and cattle.
   4. ___________ are considered as friends of farmers.
   5. Annelids have special organs of excretion called _____________.
2. 2.

   Fill in the blanks.

   1. ______________ have three pairs of jointed legs.
   2. Some _____________ have two pairs of legs per segment.
   3. A ___________ has an external coiled shell.
   4. ___________ is an example of a crustacean.
3. 3.

   Tick the most appropriate answer.

   1. The finger-like structures present around the mouth of cnidarians are called
      1. pseudopodia.
      2. tentacles.
      3. spines.
      4. bristles.
   2. Organs of excretion in annelids are called
      1. gills.
      2. nephridia.
      3. suckers.
      4. lungs.
   3. Annelids have a
      1. soft, unsegmented, bilaterally symmetrical body.
      2. soft, cylindrical, segmented, bilaterally symmetrical body.
      3. soft, segmented, bilaterally symmetrical body.
      4. soft, segmented, laterally symmetrical body.
   4. Scorpions are spiders are
      1. crustaceans.
      2. arachnids.
      3. myriapods.
      4. insects.
   5. The body temperature of warm-blooded animals
      1. keeps fluctuating.
      2. changes according to the temperature of the environment.
      3. does not change with any change in the temperature of the environment.
      4. decreases when the temperature of the environment increases.
4. 4.

   Bones with large air cavities are present in

   1. cnidarians.
   2. fish.
   3. annelids
   4. birds.
5. 5.

   Fill in the blanks.

   1. The animals without a backbone whose body is soft and often covered by a hard shell are ________________.
   2. Invertebrates with jointed legs belong to __________.
   3. The backbone of vertebrates is made up of a small bones called ___________
   4. Fishes obtain oxygen from water through ___________.
   5. Vertebrates that spend a part of their life on land but lay their eggs in water are called ___________.
6. 6.

   Differentiate between flatworms and roundworms.