Answer:
According to the biological species concept, organisms belong to the same species if they can interbreed to produce viable, fertile offspring. Species are separated from one another by prezygotic and postzygotic barriers, which prevent mating or the production of viable, fertile offspring.
Fossils can only be formed when mud, silt or tar is in the area to preserve the fossil, If erosion does not occur and allows the fossil to form, and Oxygen and microorganisms cannot decay the bones.
Answer and Explanation:
Observing population directly gives you accurate result .
Direct observation does not need any intermediary as they themselves go for survey.
So, it is cost efficient.
Whereas indirect observing may involve manipulations.
It requires someone or many to hire who helps in surveying.
It incurs cost.
Thus, direct observation is always better than indirect observation.
The answer is : Thermosphere. At this point the homosphere (troposphere, stratosphere and mesosphere) ends at about 80 km from the surface, gas molecules<span> are here</span>bombarded<span> by X-</span>rays from the sun<span> and subsequently form the ionosphere.
Hope this helps! :)</span>
