The principle of superposition states that the oldest sedimentary rock units are at the bottom, and the youngest are at the top.
Explanation:
The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer of rock is older than the one above it and younger than the one below it (Figures 1 and 2). Accordingly, the oldest rocks in a sequence are at the bottom and the youngest rocks are at the top.
the lowest stratum tend to have the slowest-moving creatures; above them are faster ones. Evolutionary scientists declare these lowest strata are many millions of years old (570 million for the oldest, the Cambrian), and the topmost to be the most recent.
<h3><u>The Food webs are preferred over food chains for representing the flow of energy in an ecosystem for the following reasons:
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The food webs are higher in complexity when compared to food chains and also, in food web, more than one primary producers is present which increases the 'flow of energy' in the ecosystem.
Food web represents the real life better than the food chains do.
Food web shows many different paths through which the organisms can be connected.
