What organisms does not have kidneys

What happens to the amount of waste in the pond as the ecosystem ages?

How does the closing of the ductus arteriosus and ductus venosus alter circulation in an infant? a. increases blood flow to the pulmonary artery and increases blood flow to the umbilical vein b. increases blood flow to the pulmonary artery and reduces blood flow to the umbilical vein c. reduces blood flow to the pulmonary vein and increases blood flow to the umbilical artery d. reduces blood flow to the pulmonary vein and reduces blood flow to the umbilical artery

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?