What are common signs of developmental disabilities in infants?

Developmental disabilities in infants often manifest through a range of observable characteristics that can indicate challenges in physical, cognitive, and social development. The signs listed in the correct answer highlight key areas that healthcare professionals and caregivers monitor to identify potential developmental issues early on.

Delayed milestones refer to the infant not meeting expected developmental benchmarks, such as rolling over, sitting up, or walking, within the typical age ranges. This delay can be a critical indicator of underlying issues. Lack of social engagement can be evidenced by minimal eye contact or a lack of interest in interacting with caregivers or peers, which can signify developmental challenges in areas such as emotional or social skills. Abnormal muscle tone may present as either hypotonia (decreased muscle tone leading to floppiness) or hypertonia (increased muscle tone leading to stiffness), and these variations can affect an infant's ability to move, and consequently, their development.

In contrast, the other options describe behaviors or characteristics that may not necessarily indicate developmental disabilities. Excessive crying and inability to sleep can be common in many infants due to various reasons including discomfort or normal developmental stages rather than specific disabilities. High energy levels and constant movement might simply reflect a particularly active child without implying any developmental issue. Rapid weight gain and excessive