How is a covalent bond formed between atoms? a: by the sharing of protons b: by the sharing of electrons c: by the transferring of protons d: transferring electrons

B. by the sharing of electrons

Answer choices A  and C are incorrect because covalent bonds form as a result of electrons (protons are kind of irrelevant). Answer choice D is incorrect because it describes an ionic bond.

Further study topics: water polarity, hydrogen bonds, free radicals, valence electrons, and more!

well, i believe that the answer is 2. : 3

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.