That would carbon dioxide
Biochemistry is the study of the actions of the main metabolic processes of living organisms, which are protein synthesis (DNA and RNA molecules, genetic codes and how they work, enzyme formation and function, etc), glycolysis (cellular respiration, aka the Krebs cycle/citric acid cycle to break down glucose molecules to release chemical energy and oxydative phosphorylation, the use of that chemical energy to form ATP molecules in which the chemical energy is put in a form the cell can use, and lipid chemistry (the study of the pathways in which fatty acids are formed into lipids and fat molecules and cholestrol formation and function).
Essentially, biochemistry covers the chemical reactions necessary for cellular and organism metabolism
Larger animals may be going into hibernation and the berries wolves eat may be out of season.
The major difference between a light microscope and a electron microscope would be that with the light microscope, a beam of light is used to focus the image. In an electron microscope, a beam of electrons is used to focus the image. Other notable differences would be with the light microscope, your specimens must be very thin; thin enough for light to pass through them. With the EM, you can place whole specimens that can generate 3D images. There is a much more complex specimen preparation process for the EM, where light microscope slide making is fairly simple in comparison. You can view live and wet specimens with a light microscope but you cannot with the EM because an EM requires specimens to be placed in a vacuum chamber. Lastly, the EM is very large and complex to operate, where the light microscope is somewhat portable. Hope this helps!