Identify environmental factors that may lead to developmental disabilities.

Environmental factors play a significant role in the development of disabilities, particularly during critical periods such as prenatal development. The correct option highlights several key influences that can adversely affect the health and development of a fetus or young child.

Prenatal exposure to toxins, such as drugs, alcohol, and environmental pollutants, can disrupt normal brain development and lead to long-term cognitive and physical impairments. Malnutrition during pregnancy deprives both the mother and fetus of essential nutrients necessary for healthy growth and development, potentially resulting in developmental delays or disabilities. Additionally, lack of access to healthcare can prevent pregnant individuals from receiving crucial prenatal care, further increasing the risk of complications and adverse developmental outcomes for the child.

In contrast, while excessive screen time and poor parenting can certainly affect a child's social and emotional development, they are not classified as environmental factors leading to developmental disabilities in the same direct and profound way as prenatal influences. Similarly, living in urban versus rural environments may impact access to resources or lifestyle experiences but lack the direct biological impacts of prenatal exposure to harmful substances or nutritional deficits. Lastly, exposure to sunlight and high altitude do not have a recognized link to the causation of developmental disabilities in the same manner as the factors identified in the correct choice.