What process added oxygen to earths atmosphere

Sammi is studying the interaction of the digestive and circulatory systems in the human body. she has listed various processes that occur in each of the systems. put the processes in order to describe the interaction between these two systems. tiles nutrients diffuse through the villi of the small intestine.digestive processes break nutrients down in the mouth, stomach, and small intestine.blood is pumped through the circulatory system to deliver nutrients to other organs.nutrients are ingested at the mouth.nutrients enter the capillaries of the circulatory system. sequence

Which describes how weathering and erosion are different? weathering is caused by water. erosion is caused by wind and ice. erosion transports sediments. weathering is a natural process.

Nasa scientists must work together to make sure that everything is correct and accounted for when launching a shuttle. besides a physicist, what other type of scientist would be in making sure that the shuttle has the appropriate type and amount of fuel to reach its destination?