Which organisms produce about half of the oxygen on earth

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?

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

Lola needs to sign 6 invitations. using stopwatch that measures time to tenths of a second, it takes lola 5.3 seconds to sign her full name. going by the accuracy of the stopwatch, which is the most accurate determination for the number of minutes lola needs to sign all 96 invitations