make a list of diet chart of 12 year old child? its urgent...................

 suman collected her saliva and mixed it with liquid A in the test tube. In another test tube, she took only the liquid A. After about 10 minutes, she added a few drops of iodine solution to the mixture in the  first test tube. it did not show any colour but when she treated the other test tube with iodine, a blue black colour appeared. now answer the following questions: 

(a) what is the aim of the activity?

(b) what is the liquid A?

(c) why did the first test tube not show any colour change with iodine solution while second one did?

(d) which enzyme is responsible for such a result?

(e) why does a piece of bread chewed for a long time tastes sweet?

A student took 2 - 3 g of substance x in a glass beaker and poured water over it slowly. He observed bubbles along with a hissing noise. The beaker becomes quite hot. Identify x. What type ofareaction is it ?

obtain the formula for the focal length of a lens in terms of object distance and magnification.

Give 4 applications of conduction, convection and radiation

I need all chemical formulas and symbols of element and compounds

a person suffering from a eye defect

uses a lens of power 1 d name the defect and nature of the lens

pls ans this fast and how to do this type of sum