Problem: - Coal is pulverized into fine powder - The coal is mixed with hot air - The coal and hot air are blown into a boiler - The coal and hot air burn over a fire - Highly purified water is pumped through pipes in the boiler - The water turns into steam - The steam presses against turbines - The turbines spin - Electricity is produced. What might be the first step of the process?

A: Coal is mined out of the ground

Problem: - The matter forms on the sea floor - Layers of sediment form above the matter compressing it - After many years the matter is compressed and heated - The result is that crude oil forms. What might be the first step of the process?

A: Living organisms in the sea die

Problem: - Water is transported to the leaves in the xylem - Energy harvested through light reaction is stored by forming ATP - Carbon dioxide and energy from ATP are used to create sugar - Oxygen exits the leaves through the stomata by diffusion - The plant reuses the water or the water exits through the stomata as water vapor. What might be the first step of the process?

A: Carbon dioxide enters the leaves through the stomates by diffusion

Problem: - Composition of blood is regulated - Volume of water in blood is kept constant - PH is kept at a constant level - Kidneys help regulate blood pressure - Kidneys stimulate the making of red blood cells - Calcium levels are maintained. What might be the first step of the process?

A:
Kidneys filter waste out of blood