Problem: - As water expands it puts great pressure on the walls of anything containing it, including any rocks which happen to be surrounding it - The force of the pressure exerted on the rock surrounding it is enough to wedge the walls of the crack farther apart, thus expanding and deepening the crack - Clay expends when wet like ice does - This causes rock to break apart - Some plants like mosses and lichens are capable of growing without soil on bare rock - When they do this their roots penetrate pores and crevices and cause rocks to split apart as the roots force their way down through the rocks - What might be the first step of the process?

A: When water freezes it becomes 10% bigger, or takes up 10% more space

Problem: - They secrete digestive juice 'externally' into the small intestine - There are enzymes for breaking down fats, proteins , and carbohydrates - Digestive juices flows from the pancreas through an excretory duct into the small intestine - When the blood sugar levels rise, as they might after a meal, insulin is released - When blood sugar levels are too low, the pancreas releases glucagon into the bloodstream - What might be the first step of the process?

A: Over 99% of the exocrine pancreas cells produce digestive juices

Problem: - Ice inside the cloud bumps around and causes electrostatic charges - The cloud becomes a thundercloud - Electrostatic energy builds and forms a strong negative charge - Positive energy is attracted to the negative energy in the cloud - This positive energy gathers on the ground - The positive energy connects with the negative energy and forms lightning. What might be the first step of the process?

A: Ice forms inside a cloud

Problem: - The cans are transported to a facility - The cans are shredded by a machine - The cans are heated to 1400 degrees to melt them - The molten metal is poured into molds - The molds are flattened and rolled into sheets to reuse. What might be the first step of the process?

A:
Put the aluminum can into a recycle bin