What is the missing first step of the following process: - Air enters bronchioles - Bronchioles have tiny air sacs called alveoli - Alveoli surrounded by small blood vessels - Oxygen absorbed by small blood vessels - Vessels deliver oxygen to every cell in the body - Blood brings carbon dioxide back to lungs - Carbon dioxide released when you exhale.
Ans: Air enters the lungs through bronchial tubes

What is the missing first step of the following process: - Water seeps into the remains - Minerals dissolved in the water form crystals - Crystalized minerals cause the remains to harden - The minerals form a fossil.
Ans: An organism dies

What is the missing first step of the following process: - Fill the tray with water from the faucet - Put the ice cube tray in the freezer - Wait for several hours - The water will freeze and become ice - Remove the ice cube tray from the freezer - Remove the ice cubes from the tray.
Ans: Take out an ice cube tray

What is the missing first step of the following process: - Bloodstream - The pancreas - Insulin lower sugar levels - Bloo sugar goes back to normal.
Ans: Sugar enters the body