The study of chemical reactions of living this is called biochemistry.
Answer:
One reason that Organism A and Organism C will be placed in different groups will be due to their MODE OF NUTRITION.
As described in the question, Organism A has an autotrophic mode of nutrition which means that it has the capability to produce its own food. Organism C is a heterotroph which means it cannot produce its own food and hence will have different properties as compared to the organism A.
prokaryotic cells do not have a nucleus.
The answer is thermal energy.