Where in the body are nitrogen compounds found?
a. proteins
b. nucleic acids like dna
c. fats
d. both a & b

I believe the answer is D. both a and b

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.