1.Classification of Porifera is based on .a) branching .(b) spicules .(c) reproduction .(d) symmetry.
.2.Metamorphosis of insects is regulated through hormone (a) pheromone . (b) thyroxine *(c) ecdysone .(d) all of these.
3.The simplest type of canal system in Porifera is.. .(a) ascon type . (b) leucon type . (c) sycon type (d) radial type.
4.Mucus helps frog in forming . (a) thick skin .(b) dry skin (c) smooth skin (d) moist skin.
5.A larval stage occurs in the life history of all members of the group (a) frog, lizard and cockroach .(b) Ascaris, housefly and frog . (c) housefly, earthworm and mosquito .(d) butterfly, frog and mosquito.
6. Budding is a normal mode of asexual reproduction in .(a) starfish and Hydra .(b) Hydra and sponges .(c) tapeworm and Hydra (d) sponge and starfish.
7. A common characteristic of all vertebrates without exception is .(a) the division of body into head, neck, trunk and tail . (b) their body covered with an exoskeletorn . (c) the possession of two pairs of functional appendages .(d) the presence of well-developed skull.
.8.When an animal has both the characters of male and female, it is called (a) super female (b) super male * (c) intersex .(d) gynandromorph.
1. (b): The phylum Porifera is divided into three classes : calcarea or calcispongiae, hexactinellida or hyalospongiae and demospongiae or Sclerospongiae, on the basis of spicules (skeleton). Class calcarea have calcareous spicules, class hexactinellida have siliceous spicules and class demospongiae have siliceous spicules or spongin fibres or both
.3. (a): Sponges belong to the phylum porifera. Ostia, spongocoel and osculum together form a canal system which is characteristic of all sponges. Canal system of Leticosolenia is of ascon type. It is the simplest type of canal system found in sponges. Water enters directly through ostia into the central spongocoel, which is lined by choanocytes, and leaves through osculum. Sycor type of canal system is found Sycon and Leucon type is found in Spongilla. There is no canal system named as radial type.
5. .d): In butterfly, the larval stage is known as catterpillar, in frog is known as tadpole and in mosquito is known as wriggler.
d): Gynandromorph is an animal that possesses both male and female characteristics because it is genetically a mosaic, i.e. some of its cells are genetically male and others are female. This phenomenon is found particularly in the insects but also appears in the birds and mammals; it is often due to the loss of an X chromosome in a stem cell of a female (XX), so that all tissues derived from that cell are phenotypically male. . Intersex is an organism displaying characteristics that are intermediate between those of the typical male and typical female of its species. For example, a human intersex may have testes that fail to develop, so that although he is technically a man he has the external appearance of a woman In super female and super male the number of female and male sex chromosomes, respectively, is above normal
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