Antigens are substances capable of mobilizing the

Antigens are substances capable of mobilizing the IMMUNE SYSTEM

Your answer would be:           IMMUNE SYSTEM

Hope that helps!            : )

The diversity index is defined as the measure of diversity that describes the number of species that is present and also the relative abundance of individual species.

The invasive species are those species that are dominant in character and their presence can cause a negative impact on the ecosystem. They have the ability to create dis-balance in an ecosystem. For example, Asian Carp, European Starling, and Water hyacinth.

An increase in the number of invasive species leads to a decrease in the diversity index. This species can alter the food web within an ecosystem by eliminating the local food sources leaving no food for the faunas.

Thus, these species must be kept under control in order to maintain a favorable condition for the other species to exist in an ecosystem.