Problem: - Composition of blood is regulated - Volume of water in blood is kept constant - PH is kept at a constant level - Kidneys help regulate blood pressure - Kidneys stimulate the making of red blood cells - Calcium levels are maintained. What might be the first step of the process?

A: Kidneys filter waste out of blood

Problem: - 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. What might be the first step of the process?

A: People separate different materials to be recycled

Problem: - Put the pot over a source of heat - Turn the heat on - Wait for a few minutes - Begin to observe small bubbles in the water - Wait until the water starts to bubble a lot - Wait until you can see steam rising from the water - Turn the heat source off - Take the pot off of the heat source. What might be the first step of the process?

A: Add water to a pot

Problem: - The movement is due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained - Sediment transport occurs in natural systems where the particles are clastic rocks (sand, gravel, boulders, etc.), mud, or clay - The fluid is air, water, or ice - And the force of gravity acts to move the particles along the sloping surface on which they are resting - Sediment transport due to fluid motion occurs in rivers, oceans, lakes, seas, and other bodies of water due to currents and tides - Transport is also caused by glaciers as they flow - What might be the first step of the process?

A:
Sediment transport is the movement of solid particles (sediment)