Is a measure of the number, variety and variability of living organisms in an ecosystem.

Biodiversity

Explanation:

Biodiversity is the variety of living beings in the ecosystem. It is typically measured by the variation at the genetic, ecosystem and species level in the living beings. The biodiversity can vary from one region to another. The terrestrial biodiversity is more near the equator, this is because of the greater primary productivity and warm climate.

d. the weight of the book

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.