Many stream organisms need clean water. Which of these ecosystems would most help the water in a stream ecosystem remain clean? Forrest, Grassland, Wetland, Cropland

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

i wish i could with all of them i can barley see the first one so here's the answer to the first one b

the answer u all are looking for is 4000000000000000000000 million years.