Questions

Dog

Object Repository means not a collection of objects

it's a common repository for all the people (testing, developers) for seeing all the data in single login.

for example QA wants to see 5 testers works then he goes  to each person login and see the data. It's very difficult job. for this we can use Object Repository.

We know that polar substances are soluble in polar solvents and non polar substances are soluble in non-polar solvents only. Here the hydrocarbons are non-polar molecular substances and water is a polar solvent. So water can't dissolve hydrocabons.

Hence, as hydrocarbons are non-polar substances, they are insoluble in water as it is a highly polar solvent. 

A 40% solution of Formaldehyde known as Formalin is used in the preservation of biological specimens because of its hardening action on proteins.