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What is Breathing?

Q. What is breathing? Ans. Breathing is an external process, in this process inhale of air and exhale of air. Or  Breathing (or ventilation) is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly by bringing in oxygen and flushing out carbon dioxide.   Breathing is also known as external respiration. It is part of respiration but not internal or cellular respiration. The process of breathing does not fill the alveoli with atmospheric air during each inhalation (about 350 ml per breath), but the inhaled air is carefully diluted and thoroughly mixed with a large volume of gas (about 2.5 liters in adult humans) known as the functional residual capacity which remains in the lungs after each exhalation, and whose gaseous composition differs markedly from that of the ambient air . Physiological respiration involves the mechanisms that ensure that the composition of the fu
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Types of Reproduction


                                       
                                        Types of Reproduction
        There are two forms of reproduction: Asexual and Sexual.
1.          Asexual Reproduction
2.         Sexual Reproduction

1.    Asexual Reproduction
Definition:
Asexual reproduction or apomixis is the formation of new individuals without involving the formation and fusion of gametes.
Or
Asexual reproduction by which offspring arise from a single organism, and inherit the genes of that parent only: it does not involve the fusion of gametes, and almost never changes the number of chromosomes.
In this type of reproduction offspring are identical to their parents.

Characteristics
i.          In asexual reproduction, only one parent is involved, so called uniparental (monoparental) reproduction.
ii.          It does not involve formation and fusion of gametes.
iii.         It involves mitotic divisions.
iv.         It involves rapid reproduction. It is primitive than sexual reproduction.
v.          It is found in lower organisms like Protistant protozoans (Amoeba, Paramecium), sponges (Scypha), coelenterates (Hydra, Tubularia, etc.) certain flat worms, some worms and tunicates.
vi.         It is absent in invertebrates and all vertebrates.


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