What can disturb or delay a child's normal development?

The correct answer focuses on the significant impact that prenatal problems or trauma during birth can have on a child's normal development. Factors such as exposure to harmful substances during pregnancy, certain maternal infections, or physical trauma during the birthing process can disrupt the healthy progression of a child's growth and development. These issues can result in a range of developmental delays, cognitive impairments, or physical disabilities.

While genetic factors certainly play a role in development, they are not the only factors that can disrupt it. Parental guidance is generally a positive influence and supports development rather than hinders it. Additionally, a healthy diet is crucial for ensuring proper growth and development; thus, it doesn't contribute negatively but rather supports the child's wellbeing.