Answer:
Until recent history,extinctions have always happened gradually and on a small scale.
Explanation:
Extinction occur when environmental factors like natural disaster,habitat fragmentation,over exploitation,global change don't favor the survival of species thus gradually leads to extinction of species.
Some times human activity becomes the major problem for extinction.More over,poor reproduction,decline in population number and genetic inbreeding also leads to extinction.
99% of all species that exist on earth become disappeared.
Evolution leas to speciation which leas to formation of new species but species become extinct when they are unable to survive against competition.
Answer:
sounds hard have a good day
Explanation:
Answer:
D
Explanation:
This is because one of its orbital shells is not filled – the one with 1 electron. This atom will, therefore, want to lose this electron – it takes less energy to do this than gain 7 electrons -- to achieve stable electron configuration. This makes this atom very reactive in a chemical reaction. Usually orbital shells of atoms begin with an S orbital shell that is filled with 2 electrons then P (x,y,z) orbital shells filled with 6 electrons total. There are also higher energy f and d orbitals that each take a maximum 10 and 14 electrons respectively. An atom is stable if its orbitals are fully filled.
Answer:
atmospheric pressure
Explanation:
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