Adenine, Thymine, Cytosine & Guanine
The most useful microscope to use would be a Compound Light Microscope. These microscopes are limited to about a good 2000X magnification. Not only can you use this to estimate the number of red blood cells, but it is good for seeing and identifying protozoa, bacteria, and organism cells.
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!
Explanation:
the amount of catalyst is same at the end as at the beginning of the reaction .