Biology practical

recently, in school we just did a practical in the laboratory. We were given 5 substances, A, B, C, D and E. All are unknown substances. These are the steps to the experiment:

1. Label the tubes A, B, C, D and E. 
2. Carefully transfer 1 spatula full of each of the substance A, B, C, D and E into the respective test tube. 
3. Add 3ml of water to each of the tube. Mix well using the wooden splinter. 
4. Start your stopwatch. 
5. Observe. Write your observations in table 1. Take readings if you have to. 
6. After 10 mins, record the observations again. 
7. What is your inference for each of the substance? Is there any evidence of life?

Physical appearance of substance A, B, C, D and E.

A: looks like sand, has not much smell.
B: when observed carefully through the hand lens, looks bacteria like formed, a bit rectangular and oval shaped, has a pungent smell
C: looks like silica gel or water baby, no particular smell
D: round and blackish, looks like pepper
E: yellowish and a bit brownish

Glucose, water and salt water are also provided to test the reactions of the substances
Why were these liquids chosen?
Glucose contains sugar and its like a source of food for the unknown substances, the substances would then react to them when placed inside glucose. Water is provides the dissolved oxygen for the unknown substances. Salt water does not allow that much dissolved oxygen in it hence it is used for drinking, if the substance needs.
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