Which of the following best demonstrates the unity among all organisms?

a. emergent properties

b. descent with modifications

c. the structure and function of DNA

d. natural selection

The structure and function of DNA.

Explanation:

DNA is present as genetic material in almost all organism except some viruses. The DNA is made of pentose sugar, nitrogenous bases and the phosphate group.

The composition of the DNA remains same in almost all organism. Four nitrogenous bases of DNA are adenine, guanine, thymine and cytosine in almost all organism. The flow of genetic material and DNA replication occurs is similar in all the organisms. DNA shows unity among all the organism.

Thus, the correct answer is option (c).