Answer:
C) X=100%; Y=0%
B) X=50%; Y=50%
Explanation:
The oldest rocks on Earth are about four billion years old. When a rock forms, it contains unstable isotope and no daughter isotopes, so every rock will contain 100% parent isotope and 0% daughter isotope.
The half-life of the radioactive isotope Of this particular rock is 5730 years. The half-life is an amount of time needed for half of the parent isotope (50%) to become a daughter isotope. In this case, after 5730 years, half of the initial parent isotope will transform to daughter isotope, which means that after 5730 years, there will be 50-50 of the parent and daughter istotopes presented in the rock. After two half-lives, there will be only 25% of the parent isotope remaining (that’s half of the previous 50% which remained after first half-life), and after three half-lives, there will be only 12,5% of the parent isotope remaining and so on.
Here you go my friend . Earth's crust is made up of rock. It is technically the first layer out 4 layers within the earth. The ocean is basically like a blanket above the crust. Our ocean's waters rest on the crust. Doesn't matter how large or how heavy the water is, our crust holds our water.
Explanation:
Fossils do tell a lot about Earth's past landscape. Age of rocks , species of animal in the past era, etc. But there are various aspects that they fail to answer. While fossils reveal what ancient living things looked like, they keep us guessing about their color, sounds, and most of their behavior. Fossils are very rare.The Fossil record is like a big jigsaw puzzle, with most of the pieces missing. Many species probably left no fossils at all.
The changes in the phases of the Moon are caused by its position towards the Sun, not as it is commonly thought that it is because of the Earth's shadow on it.
What we see from the Moon, the bright part and the almost invisible dark part (looking with bear eyes of course), is only dependent on how the Moon is positioned towards the Sun. The part that is bright is the part that faces the Sun, while the part that is dark is the part that is on the opposite side, thus not facing the Sun.
Depending on the Moon's position towards the Earth as well, we can sometimes see it as partially bright, as half bright, full bright, and everything in between, and that depends on how the Moon is positioned towards the Earth.
Hello user,
Answer:
(1) : the action or process of rotating on or as if on an axis or center. (2) : the act or an instance of rotating something. b : one complete turn : the angular displacement required to return a rotating body or figure to its original orientation.
