Answer:
H2O2 H2O CO CO2 CH4 are all compounds.
Explanation:
Compounds contains 2 or more ions of different elements in different proportion joined by chemical bonds into a molecule.
I think its C. hormones act on muscles and glands only. Because hormones act on cells, tissues, organs etc. So this is incorrect and the rest of them are correct.
In DNA, the "rungs" between the two strands of DNA are formed from the nitrogenous bases adenine, thymine, guanine and cytosine