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Subject :NSO    Class : Class 7

Digestive juices were collected from three different regions of the alimentary canal. Drops of these juices were added to wells made in an agar of starch as shown in the given figure.

After an hour, the wells were rinsed with distilled water and flooded with iodine solution. The results are given in the table.

Well 1 2 3
Colour of iodine
Blue-black Yellow - brown Yellow - brown
Which of the following correctly identifies the regions of the alimentary canal from which the three digestive juices were obtained?

AWell 1 represents region that contains an enzyme pepsin that causes the breakdown of proteins into simple substances.
BWell 2 could represent region that contains an enzyme called salivary amylase.
CWell 3 could represent region that is the longest portion of alimentary canal and receives bile juice from liver and pancreatic juice from pancreas.
DAll of these

The options are placed wrongly. Well 1 cannot turn blue-black as it has protein. Well 2 should turn blue-black because it has starches. Only option c is correct. The answer is C

Ans 1:

Class : Class 7

Ans 2:

Class : Class 8
I guess the answer is option D.. You see that if well 2 has salivary amylase, then the starch will be converted into simple sugars => No starch is found from that well (it has converted to simpler form)

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