The Punctuated Equilibrium theory proposes that a specie that appears in the fossil record will become stable. To support this theory, a fossil record serves as an evidence which includes transitional fossils. Transitional fossils refers to the remains of an organism that still exhibit traits to both the ancestral and descendant group.
<span>Viruses are regarded as being on the borderline of living and non-living because it exhibits characteristics of both living and non-living organisms. Inside a host, the virus can act as a living organism using the host's cellular system while outside the host, the virus crystallizes that makes them incapable of conducting metabolic activities. </span>
Explanation:
If the concentration of molecules outside the cell is very high relative to the internal cell concentration, the rate of diffusion will also be high. If the internal and external concentrations are similar (low concentration gradient) the rate of diffusion will be low.