Twelve pairs of ribs are attach to the second spinal region which is called the thoracic. Thoracic spine is kyphotic. Kyphotic means excessive curvature of the spine as it occurs in thoracic and also sacral regions. Thoracic spine is located in the chest area.The ribs are attach to the thoracic spine and protect the vital organs that is located thoracic spine region.
I believe it is natural selection. Natural selection is when over a period of time, traits that are formed to help the organism survive, are passed to the next generation. For example, if there were two types of rabbits. One had black fur and the other was white. They both lived in the artic. The black furred rabbits are mostly eaten by predators because their black fur is easily seen against the ice and snow. Over a period of time, the black furred rabbit would die out. The next generation would mostly have white fur to help them survive.
Its b. Ecosystem
Population is the number of a species in an area, it has nothing to do with physical characteristics.
Abiotic is just an adjective meaning not alive
Competition is just the interactions between organisms in the struggle for food, water, space, mates, and many other things again not physical characteristics
<span>Observing that fibroblasts grew better in cell culture when blood serum was added to the growth medium instead of blood plasma. Thus proving that there was a substance in serum that made it easier for fibroblasts to grow.</span>
