we should wash our hand because in experiment if any chemicals falls on our hand it may get diseases
2) we should wash our hands properly with soap after experiment because when we do experiment retouch various types of chemicals, acids, base etc. which can harm our skin very badly so it is an advise to wash our hands properly with so after experiment only for your skin it doesn't mean anymore .
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because when we burn petrol then it will work this is same like our body it is olso act as same when we burn calories then it from an energy without burning it will not from there energy
Explanation:I hope this help u........ thank you
(ii) why we should wash...