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Hello boys and girls. Welcome to a new natural science lesson. In this case, Unit 4, Plants.

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Lesson 3, Photosynthesis and Plant Respiration.

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The first question is, do plants need food?

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Here we can see a plant, water, sunlight, carbon dioxide, and oxygen.

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Photosynthesis.

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Plants need energy.

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This is the type of food they need.

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They make their energy through the photosynthesis.

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Let's do the math.

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Photosynthesis equals to minerals plus water plus sunlight plus carbon dioxide equals to energy plus oxygen.

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As we can see here, minerals, water, sunlight, carbon dioxide, energy, which is the food of the plant, and oxygen, O2.

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Here you have the formula again.

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Why are plants so important for us, humans?

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On the one hand, plants need carbon dioxide and release oxygen.

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On the other side, humans need oxygen and release carbon dioxide.

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This is like a cycle.

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In your notebook, you have this drawing of the photosynthesis process.

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As we can see here, number 1 is water, blue, number 2 are minerals, brown, number 3 is

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carbon dioxide, red, number 4 is sunlight, yellow, number 5 are the stem and leaves,

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green and number 6 is oxygen.

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In the following page we will explain all these numbers.

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one, the roots absorb water from the soil. Number two, the roots absorb minerals

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from the soil. Number three, the leaves absorb carbon dioxide from the air.

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Number four, the leaves absorb sunlight. Number five, water and minerals pass

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through the stem to the leaves. Number six, plants make energy and release

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oxygen which is good for us humans let's talk a little bit now about respiration

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as we can see here we have a day time and the night time plants also need

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oxygen to breathe day time night time the main difference is that during the

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daytime, within the photosynthesis, plants are producing oxygen. They release the

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oxygen that they don't need, but they use a little bit of oxygen. What happens

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during the night time there is no sun no sunlight and plants do not produce oxygen so they take it

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from the air remember this is the main reason why we need plants and plants also need us

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thank you very much for listening