Problem: What is the missing first step of the following process: - Food is squeezed down the esophagus when you swallow - Acid and enzyme in the stomach break the food down - Releases nutrients - Food then pumped into small intestine - Fluid and enzymes from liver and pancreas pumped into small intestine - Help break food into smallest molecules - Nutrients pass through wall of small intestine - Nutrients absorbed into blood stream - Unused materials passed into large intestine to become fecal matter.

A: An enzyme in saliva begins to break down carbohydrates

Problem: What is the missing first step of the following process: - The sweat changes into a gas - Heat is drawn from the sweat - This process draws heat from the body - The evaporation also cools the remaining sweat on the body.

A: As the sweat evaporates the sweat sheds molecules into the air

Problem: What is the missing first step of the following process: - Sediment builds up over the remains - The remains decompose, leaving only trace amounts - The remaining parts over the years are replaced with mineral - A fossil is formed -

A: Animals and plants die in soft soil or mud

Problem: What is the missing first step of the following process: - Mix gets inducted into cylinder - Piston compresses the mix - Spark plug emits a spark that ignites it causing combustion - Combustion gases expand - Pushes piston during power stroke - Exhaust valve opens to vent exhaust out tail pipe.

A:
Fuel mixes with air