Fish have a circulatory system with a two-chambered heart.
Birds also have four-chambered hearts.
Birds and fish have different heart circulatory systems.
What aspect is different for Bird and fish hearts

[A] circulatory systems
[B] matter vibrating
[C] tissue
[D] it keeps an organism warm
[E] members of their own species
[F] heat produced
[G] blood
[H] type of organs