What are the physiological characteristics of premature infants?

The child born 37 weeks ago is a premature infant. The physiological characteristics of premature infants are light weight, generally less than 2500 grams, thin red skin, more fetal hair, weak neck muscles, low muscle tension of limbs, incomplete palm prints, etc., because the child's digestive and respiratory system is not perfect, there will be choking cough, easy to spit milk.