Problem 1. During human embryonic development, many neurons arise and form connections with one another. However, much later these same neurons are found to be absent. Describe the process that accounts for this loss of early neurons, and explain how this process achieves the changes described.
Problem 2. The transmission of genetic information from parent to daughter cells is highly accurate. Describe the features of DNA replication responsible for this fidelity of information transfer. Explain why this mechanism allows the high level of accuracy of information transfer that is observed.
Problem 3. DNA is the primary source of heritable information in cells. Explain how the chemical structure of DNA makes this possible.