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P Priyanka Kumari
Three groups of plants that bear archegonia are given below: Bryophytes Pteridophytes Gymnosperms. The life cycle of a pteridophyte, then it consists of two morphologically distinct phases: (i) The gametophytic phase (ii) The sporophytic phase. These two phases come one after another in the life cycle of a pteridophyte and this phenomenon is called alternation of generation. The gametophyte...

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B Bipasha Kumar

It's called dependence and addiction. If the use or intake of alcohol is suddenly discontinued it leads to withdrawal symptoms.

 

Taenia ( Tapeworm) Ascaris (roundworm) Ancylostoma (hookworm) Enterobius (pinworm) Wuchereria (filarial worm)
(a)-(viii), (b)-(v), (c)-(iv), (d)-(i), (e)-(ii), (f)- (vii), (g)- (iii), (h)- (vi)                   (a) Operculum                    (viii) Osteichthyes                     (b) Parapodia                    (v) Annelida                     (c) Scales                          (iv) Reptilia                     (d) Comb plates                 (i) Ctenophora                     (e) Radula...
No, the number of eggs produced in oviparous animals and young ones in viviparous animals are not equal. It is because oviparous animals lay eggs outside the body of female in water, land etc so these eggs do not get the conditions that are necessary for the development and hatching of the eggs. Thus, due to the lack of parental care out of the total eggs produced the chances of survival are...
Modifications in birds to help them fly are as follows: 1. The bones of birds are pneumatic. These contain air cavities making the bones light. This feature helps the birds in flying. 2. The body of birds is streamlined offering least resistance while flying. 3. Flight muscles are well developed 4. Forelimbs of birds are modified into wings to allow flying. Hindlimbs are used for walking,...
The air bladder is found to be present in the members of class Osteichthyes while it is absent in Chondrichthyes. The main function of air bladder is to regulate buoyancy and help the fishes to float in the water. It also prevents them from sinking in the water. Since Chondrichthyes do not have air bladder they have to swim continuously to avoid sinking. 
Phylum chordata includes animals characterised by the presence of notochord. This phylum includes sub-phyla urochordata, cephalochordata and vertebrata. In vertebrates, the notochord is replaced by vertebral column, in urochordates and cephalochordates vertebral column is absent. Thus, all vertebrates are chordates but all chordates are not vertebrates as they can be urochordates and...
(c). Echinodermata Water vascular system is a characteristic feature of echinoderms which help in locomotion, respiration and capturing of food. 
The reasons for arthropods being the largest group of animals are as follows: 1.  Presence of tough cuticle for protection of the body. It also helps in tolerating diverse terrestrial conditions.  2. Presence of striated muscles for quick movements 3. Tracheal respiration for direct supply of oxygen as in insects 4. Presence of jointed appendages for performing diverse functions 5. Well...
Platyhelminthes are mostly parasites. The peculiar features of platyhelminthes are as follows  1. The body of platyhelminthes is covered by thick body covering i.e. tegument. It protects the animal from the action of digestive enzymes of the host.  2. The body of platyhelminthes is dorsoventrally flattened. 3. Platyhelminthes possess adhesive structures such as suckers and hookers that are...
The differences between direct and indirect development are as follows Direct development   Indirect development In this type of development, an embryo develops into a young one without any intermediate larval stage In this type of development, an embryo develops into a young one with some intermediate larval stages.  Young ones resemble the adult Young ones do not resemble the...
The differences between intracellular and extracellular digestion are as follows Intracellular digestion   Extracellular digestion The process of digestion of food takes place inside the cells The process of digestion of food takes place outside the cells in the alimentary canal. Only a few enzymes are involved in the process of digestion A number of enzymes are involved in extracellular...
              (a) All mammals (except a few) have seven cervical vertebra.               (b) The number of phalanges in each limb of human is 14.               (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely troponin and tropomyosin.               (d) In a muscle fibre Ca++ is stored in sarcoplasmic reticulum.                (e)  11th and 12th pairs of...
  (f) between pubic bones in the pelvic girdle ball and socket joints are present
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