Complex sentence: The hearts pump hemolymph into the sinuses of the hemocoel where exchanges of materials take place.of hemolymph needed for such a system is kept to a minimum by a reduction in the size of the body cavity.
Split into simpler sentences: The hearts pump hemolymph into the sinuses of the hemocoel where exchanges of materials take place. The volume of hemolymph needed for such a system is kept to a minimum by a reduction in the size of the body cavity.