The Earth is layered because of the difference in the density and the pressure experienced by the elements. The denser layers tend to be closer to the center and the lighter layers float on the top. The differences in the pressure experienced by these layers also keeps them separated. The pressure experienced by the center of the Earth is greater than the upper layers, and hence, the core is in liquid form because the pressure is not enough for it to remain in the solid state.
This led to the layering of the Earth's surface.
Homologous and analogous structures are two types of evolutionary evidence, taken together, provide strong evidence for when extinct species most likely diverged from common ancestors, relative to other events happening on Earth.
Several types of evidence support the theory of evolution: If two or more species share a unique physical feature, such as a complex bone structure or body plan, they can all inherit this property from the common ancestor. Physical traits shared through evolutionary history (common ancestor) they say they are homologous. Not all physical properties that look similar are signs of common ancestry. Some physical similarities instead are analogous: they evolved independently in different organisms because organisms lived in similar environments or experienced similar selective pressures.
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It is because all these three elements contain ionic properties and they have only one element in their outermost shell
Answer:
The answer is statement 1, 2, and 3
Explanation:
A hypothesis is a starting point for further investigation, therefore a hypothesis will always be a possibility at least until it is tested.
Variable is a factor that is liable to vary or change.
A hypothesis without being tested is merely a statement or an explanation made on the basis of limited evidence. Therefore it is unsure whether the said statement is true or not.
A hypothesis can still be proven by further investigation with different variables
Answer:
d.The wing-assisted incline running theory postulates that wings were initially used to maintain balance while climbing up slopes.
Explanation:
Two theories were given to explain the origin of avian flight. The top-down theory suggested that the birds' ancestors were tree dwelling species. They took help of wings to glide from tree to tree in order to avoid predator or catch prey. The bottom up theory suggested that the birds' ancestors were ground dwelling species. They took help of wings to maintain a balance and provide a lift for efficient running.
Wing-assisted incline running was a mixture of both the above theories and gave a balanced view point. According to it, birds' ancestors used wings to maintain a balance while running up inclined slopes. The wings helped them to save energy while scaling slopes and eventually a flight mechanism was also developed.
