Answer:
they must have same atomic number and different atomic mass
Explain more so i could answer it!!
The Answer is D cause of the people going back and forth.
Answer:the branch of science which examines the material of the universe and changes that these materials undergo
Chemistry deals with composition,structure,properties of matter and changes that these materials undergo
Presumptive tests, also known as preliminary tests or field tests, allow drugs to be quickly classified into a particular chemical group, but do not unequivocally identify the presence of a specific chemical compound.