Background extinction refers to the normal extinction rate. These are species that go extinct simply because not all life can be sustained on Earth and some species simply cannot survive. Mass extinction is a widespread event that wipes out the majority (over 50%) of living plants and animals.
The answer is D because the layers all the way at the bottom had to be there for other layers to be built on top
<span>developing a technique for observing an object that has yet to be observed
</span><span>Thus, to achieve the creative approach above the researchers must utilize and apply the </span>scientific method in gathering, interpreting and analyzing empirical evidence<span>. </span>
<span>Empirical evidence, data or knowledge is an obtained set of facts or figures or existing and presenting data that was yielded during the process of experimentation or scientific discovery. These empirical data or evidence is further studied and investigated by the scientist in a formal scientific approach which follows the steps of observation, making a hypothesis, gathering data, interpreting data and evaluating the data. These steps of the scientific approach are vital in the course to explain and discuss the result and evidence obtained during the process. </span>
A Boundary Is A Line That Marks A Limit Of Space. So If You Live In A Neighborhood, Then There Would Be Fences, And That Would Be A Boundary line. It Marks Space And Divides Space. Hope That Helps.
