What is the missing first step of the following process: - Once in the lungs, oxygen is moved into the bloodstream and carried through your body - At each cell in your body, oxygen is exchanged for a waste gas called carbon dioxide - Your bloodstream then carries this waste gas back to the lungs where it is removed from the blood stream and then exhaled - Your lungs and respiratory system automatically perform this vital process, called gas exchange -
Ans: He air we breathe contains oxygen and other gases

What is the missing first step of the following process: - Two types of proteins exist in filaments in the muscles - The filaments move when the brain instructs them to - The motion of the filaments cause the muscle to shorten and contract - Opposing pairs of muscles exist in order to provide the necessary range of motion.
Ans: Electrical signals in the brain travel through nerves to muscles

What is the missing first step of the following process: - The magma cools - Particles inside the magma move closer together - Crystals are formed - The crystals contain minerals.
Ans: Magma comes up to the surface of the earth

What is the missing first step of the following process: - The liver uses enzymes to clean the blood - The cleaned blood is expelled - The liver creates bile from the items filtered - The liver takes energy and stores it as glycogen - The bile is sent to the intestines.
Ans: The liver takes in blood from the rest of the body