Answer: incubates

AnswerCrossword Clue
INCUBATESHatches
INCUBATESSits on to keep warm, say
incubatesDevelop slowly without outward or perceptible signs
incubates(of a bird) Sit on (eggs) in order to keep them warm and bring them to hatching
incubatesINCUBATE, to warm eggs for hatching
incubatesHave an infectious disease developing inside one before symptoms appear
incubates(esp. in a laboratory) Keep (eggs, cells, bacteria, embryos, etc.) at a suitable temperature so that they develop