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To ensure their sexual reproduction, most plants produce flowers. 

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These contain the reproductive organs. 

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But, in order to ensure genetic mixing, plants avoid self-fertilization.

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But they are not able to move around. So how do they do it?

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Well, they are assisted by the wind, and by insects or other animals.

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The male components are grains of pollen, contained in the stamens. 

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The female components are the ovules, well sheltered within the pistil.

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In landing on a flower to collect nectar, 

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an insect carries pollen that has most often come from another flower.  

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This pollen is deposited on the stigma, the uppermost part of the pistil.  

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This is pollination.

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The ovule is located in the ovary, at the bottom of the stigma, 

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far away from the stigma where the pollen grain was deposited.  

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The pollen grain will produce a long tube down to the ovule, 

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which it will then fertilize.

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But what becomes of these organs after fertilization?

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The ovule transforms itself into a seed that contains the embryo, 

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surrounded by nutritional reserves that will be used at the time of germination. 

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The rest of the flower dries up while the ovary transforms itself into a fruit.

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Pollinating insects are indispensable for the reproduction of most fruit trees 

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and food producing plants. 

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Their disappearance would thus doom quite a number of plants to extinction.