Hello Doctor, My baby was born full-term on 27 September 2025 with a birth weight of 3 kg. He is now around 10 months old and weighs 9.5 kg. He is breastfed and also eats solid food well (about half a bowl twice a day). I am concerned about his motor development. He can roll over on his own, crawls very fast on his tummy (army crawling), bears weight on his legs when supported, and can sit only for about 2–4 minutes without support before losing balance. He is not yet getting into the hands-and-knees crawling position and is not crawling on all fours. He also cannot stand without support. His other developmental milestones seem good. He smiles, makes good eye contact, responds to his name, understands simple interactions, says sounds like "mama" and "papa," claps, and holds toys well with both hands. Could you please advise: 1. Does this suggest an isolated motor developmental delay? 2. What could be the possible causes? 3. Which investigations do you recommend (ultrasound, MRI, ,