Q: 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

Q: What is the missing first step of the following process: - The roots of the growing plants start to break up the rock - The plant acids dissolve the rock - The rock is broken down into smaller pieces - Erosion begins.
A: Plants start growing on or near the rocks

Q: What is the missing first step of the following process: - The glucose and oxygen create carbon dioxide - The cells release energy - The cells don't have enough oxygen to repeat this - The cells obtain more oxygen from the air - The cells repeat this process.
A: Cells obtain glucose and oxygen

Q: What is the missing first step of the following process: - The recyclable materials go to a recycling center - The recycling center further separates the materials - Large equipment compacts the materials into bales - The recyclable materials are shipped to other recycling centers - The other recycling centers further process the materials that center specializes in - The materials are purchased by manufacturers - The manufacturers process the recycled materials the same way they would use new materials - The recycled materials are incorporated into new products.
A:
People separate different materials to be recycled