Why is the blood that flows from the lungs toward the heart a brighter red then the blood that flows the other direction

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

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

Ascientist discovers a new body between the orbit of neptune and the kuiper belt. the object is round and travels in an orbit around neptune with other space objects. the scientist claims that she has found a new dwarf planet. where is the scientist’s error? the object is an asteroid, not a dwarf planet.the object is a moon, not a dwarf planet.the object is not a dwarf planet because it travels with other objects.the object is not a dwarf planet because it is round.