What is the missing first step of the following process: - Engines produce carbon dioxide - Living things produce waste - Waste decomposes - Decomposition produces methane - Water evaporates - Water vapor joins the atmosphere - Carbon dioxide, water vapor and methane are greenhouse gases -
Ans: People breathe and expel carbon dioxide

What is the missing first step of the following process: - The pancreas creates juices that help digest food - The pancreas releases the juices into the stomach - Trypsin and chymotrypsin digest protein - Insulin is produced to move glucose from the blood - The enzymes begin producing again.
Ans: The pancreas detects chemical changes in the stomach

What is the missing first step of the following process: - The fault lines grow over time - The rocks on each side of the fault lines rub against the rocks on the other side of the fault line - The rocks put pressure on each other - The rocks break from the pressure - The breaking of the rocks releases a lot of energy - The energy causes seismic waves - The seismic waves make the earth shake.
Ans: Fault lines appear underground

What is the missing first step of the following process: - The animal finds or builds a suitable place to hibernate where they can stay warm and protected - The animal moves into their den - Their heart rate and breathing slow down to conserve energy - They emerge from the den when the weather is warming up again.
Ans: An animal eats a lot of food to fatten up