Answer the following question given this paragraph: 

The related field of biochemistry overlaps to some extent with organic chemistry. Biochemistry is the study of the chemistry of living systems. Many biochemical compounds are considered to be organic chemicals. Both of the molecules shown above are biochemical materials in terms of their use in the body, but organic chemicals in terms of their structure and chemical reactivity.


Q: Biochemistry is the study of the chemistry of?

 Choices:

- the Earth

- inorganic matter

- abiotic factors

- living systems

A:
living systems
