Answer:
Sampling
Explanation:
Sampling is a statistical procedure in which a selected number of observations is used to represent the whole observation. When we take an area and we use the population to estimate that of other areas or the whole population, we are simply sampling. Sampling is very important to some specific forms of observations. Sampling can be done randomly or in a systematic way. The goal of sampling is using the part to represent the whole.
A dead star does indeed becomes a black hole. In fact, even the sun will turn into a giant black hole and kill us all. (That's in millions of years, so something else will wipe out the human race)
Hope this helped! :P
Answer:
B) Oxygen
Explanation:
The atmosphere of Earth hadn't always had the compostion it has at present. When the atmosphere formed, ti was much different than what it is now, and that is due to certain codnitions that were present, but also due to certain conditions that were lacking.
The oxygen is a gas that is relatively abundant in the atmosphere at present, but in the distant past it was like that. The amount of oxygen in the Earth's atmosphere initially was very small, practically having no influence on anything.
This all started to change with the appearance of the first organisms on Earth. The first organism were producers. They were carbon based organisms that needed carbon dioxide in order to produce energy for themselves. A waste product from the process of photosynthesis, through which the energy was produced, was the oxygen. As more and more producers started to occupy the planet, more and more oxygen was pumped up into the atmosphere.
This led to significant changes on Earth. The oxygen made the oceans and the land much more suited for development of more complex organisms. The atmosphere cooled off because of the oxygen, thus the global temperatures became much more pleasant. Also, the oxygen started to contribute much more corrosion, as it has the ability to destroy the metals when they are exposed to it.
