Answer:
A
Explanation:
The great contribution of Tycho Brahe was to observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion.
Tycho Brahe was a danish noblemen and an astronomer his major work was regarding the developing astronomical instrument to study the stars and pave the way for future discoveries.
Answer:
TRUE
Explanation:
The earth is comprised of three distinct layers namely the core, mantle and the crust. The core is the extreme interior layer which is comprised of the denser elements like iron, nickel and other siderophile elements. Thee denser minerals are deposited, by sinking into the core of the earth forming the highest density layer. The core was formed about 1 to 1.5 billion years back.
Whereas, the least dense elements were concentrated in the upper region of the earth forming the crust. These are the lighter elements so it did not get sink into the bottom. But still many of these elements are found in association with the core rocks. There occurred constant evolution on the crustal portion of the earth.
Thus, these elements are found in larger proportions in the crust and were formed during the initial formation of the earth.
Hence, the above-given statement is True.
Answer and Explanation:
We realize that the new plate made at the MOR, i.e., Mid Oceanic Ridge which is called divergent plate limit or constructive plate edge and consequently that oceanic plate is devoured or destructed at the destructive plate limit.
Sub-duction happen at the subduction zone where a high thick and inflexible plate going down relative to the another less thick plate.
As the outermost layer of the ocean get more seasoned it is vulnerable to subduction.
The period of subduction potential is 125 to 200 million years. Since when an oceanic plate gets more seasoned it becomes colder, progressively unbending and increasingly denser as a result of mafic constituents and submerged yet in the case of continental plate, they are constituted of felsic or granitic piece which is comparatively lighter.
So constantly denser plate i.e oceanic plate moves down relative to continental plate or plate which is less dense.