While scientists have made enormous discoveries, there is always more to learn. Knowledge is built on and reviewed. Sometimes new information reveals an error in understanding from the past. The study of how the world works is always ongoing.
It means that all the organisms in that community rely on one another to survive.
<span>It is going to depend on what you consider stable. A
diverse population would be more resistant to disease because of simple
biology. The more sources for possible resistance the better the
heterogeneous pool will be at resisting disease. You also have to take
in to consideration things like the availability of modern medicine and
the ability to be isolated during illness. </span><span>
Personally I think it has to do with the fact that many of the worlds
more diverse population centers are also many of the worlds largest
population centers which make them less prone to invasion on that basis
alone. </span>
All mentioned complexes (receptor-hormone, antibody-antigen, enzyme-substate) are involved in a molecular recognition.The molecular recognition involves <span>non-covalent </span> interaction between molecules. To form complex, molecules must be complementary in shape and charges, and usually, they are compared to key and lock. This way, the selectivity and specificity of recognition between molecules are assured.