Bio Qs tell me!

8)Why need to put leave in hot water bath,also put in the test tube with alcohol when testing the presence of strach?

9)Is carbon dioxide the only gas cause green house effect?

10) Untreated domestic sewage contains mainly

A:Faeces

B:Urine

C:Waste paper

D:Waste water

2 個解答

評分
  • 1 十年前
    最愛解答

    8) put in the hot water bath is becoz we want to kill the plant cell on the leave so metabolic activities will not affect the reaction between starch and the iodine solution afterwards.

    Put it in alcohol is because we want to decolourize the leave so the chlorophyll are removed and they will not affect the reaction as i have stated

    9) No

    Actually, greenhouse gases are refer to gases which can trap heat in the atmosphere

    Water vapour also has this kind of properties.

    There are other examples: SO2...NO2....etc.

    10) D

    by common sense only

  • 1 十年前

    8) Starch- Put leave in hot water to kill leaf cells

    Put in alcohol to decolourize the leaf and remove cholorophyll

    9) No. There are other gases like carbon monoxide, sulphur dioxide, etc.

    10) D: waste water

    資料來源: Me
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