Ais the smallest particle of a substance that has all the properties of the substance.

Consider the last statement in the prompt: "people take such environmental factors into account in their choices when deciding where to live." do all people have a choice as to where they live? what factor plays a key role in this decision and may therefore play a large role in determining quality of life?

What is the next step in muscle contraction after the actin changes shape? (apex)

What does the number 18.9984 represent in the image?