Answer:
If there wasn't a lot of organisms and energy in the productive part of the triangle, then there wouldn't be a lot of third level organisms. The energy piramid would be a lot smaller then what it is here, and maybe if the energy source was low then there might not be such a vast varity of animals in the ecosystem.
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Answer: Layer a is 500 million years old.
Explanation:
Trilobite is a member of the group of extinct arthropods found as fossils and they can be identified by the three-lobed as well as three segmented forms. These were the marine animals. These were appeared initially in the Cambrian Period. They used to live 542 million years ago so the fossils can be estimated to be aged of 500 above years old. These animals used to dominate in the sea area.
The right answer is <span>Refractory period.
At the moment when the action potential is emitted, the fiber being depolarized, it is impossible to depolarize it again. It is, therefore, necessary to wait until the membrane potential returns to a value below the critical threshold in order to be able to excite it again. We are thus led to distinguish two periods that characterize its excitability.
An absolute refractory period: during which any stimulation, even supraliminal, is ineffective since the fiber is already depolarized.
A relative refractory period: during which a second action potential can be omitted provided that the depolarization produced by the excitation reaches the critical threshold, which implies that it is more important since the value of the resting potential has not been restored yet.</span>
Answer: The answer would be Substrates
Explanation:
Radioactive dating works on the principle that a radioactive isotope can decay into the stable daughter nuclei at a constant rate. Geologist generally use the principle for half life. Half life is the time required for half of the radioactive substance to decay. This is constant for a particular element.