incubator

newborn, a newborn baby

indispensable, essential

indispensability, being essential

nursing, childcare for infants

take care of an infant, nurse an infant

護る: to protect, to defend / to watch carefully / to abide (by rules), to observe (regulations)

(archaic) to stand watch over something, to be on the lookout for something (such as a watchman controlling entry to a place) / (archaic) to protect or defend something, to ensure that something is safe

life; one's existence

(Classical Japanese) to be watching continuously, to be on watch repeatedly, to be on look out / (Classical Japanese) to protect something, to take care of something