Answer:
Options (1), (2) and (3)
Explanation:
Alfred Wegener was the person who first invented the continental drift theory. He observed that the continents move from one place to another with respect to a fixed point. He put forward many pieces of evidence but he was unable to explain the main mechanism that is responsible for these motion of continents.
The pieces of evidence that were given by Alfred Wegener supporting the continental drift theory are-
(a) The continents move slowly and continuously from one place to another and the edges of these continents perfectly match with the other.
(b) Similar fossil assemblages were found in currently separated continents.
(c) Similar rock types are also found and suggested that the continents were once all together forming a huge landmass which is known as the Pangaea.
Later this theory was modified into a more simple and universally accepted theory which is commonly known as the Plate tectonic theory.
Hence, the correct answers are options (1), (2) and (3).
Answer:Nicholas Steno first formulated the principles that allow scientists to determine the relative ages of rocks in the 17th century. Steno stated that sedimentary rocks are formed in continuous, horizontal layers, with younger layers on top of older layers.
Explanation:
Answer:
At the boundary with the core.
Explanation:
The mantle is the second layer from the top. It is bordered by the lithosphere above it, or rather by the crust, and by the outer core below it. The mantle is a layer which is in viscous state, being mostly consisted of molten metals and rocks. The temperature of this layer is not the same all throughout it, but it varies a lot. The temperature at its top part is around 200 C degrees, while the temperature at its bottom is around 4,000 C degrees. There's two reasons for this. One is that the core is very hot, so it makes the bottom part of the mantle very hot as well, and the other one is that the lithosphere is much cooler, as well as constantly getting new, cold, crust in it, which makes its top part much cooler. The mantle is the layer responsible for the movement of the tectonic plates on the surface, as it is the layer where the convection currents occur and drive the plates' movement.
Answer:
The Sun
Explanation:
The sun does not move or rotate and hence cannot retrograde, however the other planets rotate. Some astronomers define retrograde motion as the Westward movement of the planets relative to the sun, based on this definition, all the planets experience retrograde movement. On the other hand, while some astronomers define retrograde motion as the movement that the other planets make when earth passes them while orbiting the sun. Based on this second classification, Mercury and Venus do not retrograde relative to the earth because they move faster than the earth.
