The flow of energy from one level to another does not happen with 100% efficiency. The producers only transfer 10% of the energy they absorb from the Sun. The major chunk of the absorbed energy goes into the growth of the producers, the rest gets lost in the form of waste (shedding of leaves, reproduction, etc.) and the remaining 10% is the amount that is available to the primary consumers. So by this logic, if there is 150,000 KJ of energy available at the producer level, then, only 15,000 KJ of energy will get transferred to the primary consumers.
Answer:
C. At least five mass-extinction events have occurred during the last 500 million years.
Explanation:
- The history of mass extinct is related to the five mass extinctions that are caused over by the 350 million years n which many species have disappeared in there short geologic time.
- A massive extinction is caused in the Permian Triassic extinction event i.e about 250 mn years ago which on an estimate has killed 90% of the species.
- The Cretaceous–Paleogene extinction event that occurred over 66 million years ago is known to have wiped out the dinosaurs and many other species.
The UV rays cause sun spots due to reaction from the radiation.
The new population that experienced natural selection is now better fit or more adapted to the environment than the old population