Human migration is the movement over long distances, movement from one country/region to another ) by people . Humans moved because of the c<span>hanging climate and landscape and inadequate food supply. </span>The first human movement was t<span>he movement of </span>Homo erectus<span> out of Africa across </span>Eurasia<span> about 1.75 million years ago. </span>
Than industrialization<span> encouraged migration wherever it appeared.
Wars also created migration. (</span><span>The First and Second World Wars, and wars, genocides, and crises sparked by them, lead to migrations).</span>
Chloroplasts are organelles found in plant cells that conduct photosynthesis. Chloroplasts absorb light and use it in conjunction with water and carbon dioxide gas to produce food for the plant.
Vertebrae/Backbones I think.
Endosymbiotic prokaryotes.
The energy not used by an original organism being consumed is being transferred "flowing" to the organism that is consuming the original one, thus being the flow of energy throughout an ecosystem.