Weaker, less evolved living organisms die in relation to survival skills, but the better ones stay.
For artificial selection, people select organisms based on what advantages they have to make them better.
Answer:
The geosphere transfers carbon to the biosphere when volcanic eruptions occur. Burning fuels like carbon dioxide, fossils, gasoline also transfers carbon from the geosphere to the biosphere.
Carbon is incorporated into the geosphere when an organism dies. The carbon then forms fossils fuels etc. which are consumed by humans. The shells becoming limestone also transfers carbon. These limestones are used by humans for various purposes.
Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for other chemical processes (such as, notably, ammonia, nitrate and nitrogen dioxide).
Nitrogen fixation is performed naturally by certain types of anaerobic bacteria. Legumes such as clover contain symbiotic bacteria of this type within nodules in their root systems, producing nitrogen compounds that help to fertilize the soil. See George Washington Carver.
Nitrogen can also be artificially fixed for use as fertilizer or in other industrial processes. The most popular method is by the Haber process. Artificial fertilizer production has achieved such scale that it is now the largest source of fixed nitrogen in the Earth's ecosystem.
(This is the definition from the http://encyclopedia.kids.net.au/page/ni/Nitrogen_fixation website)
Answer:
Every sensory neuron is a (an) stimuli to the central nervous system, and every motor neuron is a(an) transmitter from the central nervous system.
