Miks õhk on vajalik?

1.Millised allpool toodud väidetest on õiged?
   Kui väide on vale, kirjuta, kuidas võiks selle lause kirjutada õigesti!

a) Maad ümbritsev atmosfäär koosneb hapnikust, mida elusolendid vajavad hingamiseks.
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b) Atmosfääri koostises on hapnikku, mida me hingame, umbes viiendik
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c) Taimed tarvitavad õhust lämmastikku ja toodavad hapnikku.
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d) Taimed tarvitavad hingamiseks õhuhapnikku
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e) Hapnikku vajavad organismid hingamiseks.
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f) Õhk on gaaside segu.
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g) Peale gaaside leidub õhus veeauru, tolmu ja mitmesuguseid saasteaineid.
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h) Saasteained ei ole tervisele ohtlikud.
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i) Õhk koosneb ainest - selles saavad levida helid.
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j) Õhk on läbipaistev ega koosne ainest.
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k) Õhurõhk tekib pilvede rõhust maapinnale.
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l) Õhurõhk tekib õhukihi rõhust maapinnale.
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m) Me ei tunne õhurõhku, sest oleme sellega harjunud.
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