Q: What is the missing first step of the following process: - Air enters bronchial tubes - Air is then split into the bronchioles of each lung - Bronchioles have alveoli which are tiny air sacs - Alveoli is surrounded by many small blood vessels - Oxygen passes through alveoli into blood vessels - Blood leaves the lungs as it travels through the body - Blood carries carbon dioxide back to the lungs - Carbon dioxide released when you exhale.
A: You breathe air in

Q: What is the missing first step of the following process: - They process it with millions of tiny nephrons - Remove all the waste - The kidneys return the blood back to the body through the renal artery - Send the urine with the waste to the bladder through the ureters.
A: The kidneys receive blood from the renal artery

Q: What is the missing first step of the following process: - Causes them to absorb aluminum from soil - The water runs off from the soil into lakes, streams, etc - Fish and their eggs die - Frogs and plants die - Insects and other wildlife die - The ecosystem is out of balance, causing further problems -
A: Acid rain makes waters acidic

Q: What is the missing first step of the following process: - The egg hatches to form a larva, also called a caterpillar - The carterpillar molts (loses its skin) many times as it grows - The caterpillar then forms itself into a pupa, or chrysalis - The caterpillar in the chrysalis begins change, a process called mmetaphorphosis - The caterpillar completes its metamorphosis and has turned into a butterfly - The adult butterfly emerges out of the chrysalis and flys away! -
A:
The butterfly starts as an egg