All plant and animal groups existing together and the physical factors with which they interact compose an ecosystem<span>.</span>
Body needs an approximate 10% fat
Answer:
The process by which organisms that are better suited to their environment than others produce more offspring. As a result of natural selection, the proportion of organisms in a species with characteristics that are adaptive to a given environment increases with each generation.
Explanation:
Answer:
In the course of evolution mammals are the animals which are evolved recently as compared to other groups such as fish, amphibians, or reptiles.
In addition, fur or hairs on body, mammary glands, middle ear bone, warm-blood, et cetera are the characteristics of mammals.
These characteristics were evolved during the course of evolution; they were not present in ancestral organisms.
However, tail, gill pouches, et cetera are characteristics of our ancestral groups. Thus, characters can be sometimes observed in mammals.
But mammals characteristics can not be observed in organisms which were evolved before mammals such as fishes, amphibians, reptiles, et cetera.
On site means insitu.
invitro means in glass like a test tube.