where both parents equally share the duties of caring for the young; usually formed by monogamous, open-water brooders, although exceptions are common, e.g. in the Cichlidae. Sexes are difficult to separate on external experience. Also called parental family
те, кто связаны узами брака или отцовства-материнства - т.е. "малая семья" (мать, отец и дети) пять наций, владеющих ядерным оружием (США, Россия, Британия, Франция и Китай)