Answer:
[a] varies in its characteristics according to local environmental circumstances
[b] becomes common within a species through natural selection
[d] tends to promote the well being of an organism in its natural or social environment
Explanation:
The adaptive traits in the living organisms have a simple basic role, that is to make the organism better suited for survival in its environment. The adaptive traits come in all sorts of different shapes, be it some that are manifested in the physical appearance or in the behavior of the organisms. Adaptive traits can be increased speed, prolonged neck, living in a groups, developing thorns and many more. This type of traits occur when the organisms face increased competition or when the environment in which they live starts to change, so in order for them to survive, they start to develop traits that will make them better suited for the new conditions and more competitive. The main principle through which the adaptive traits are transferred and rapidly increase in a population is through natural selection, as the organisms choose the ones that have advantageous traits for their mates, while they live aside the others.
OK so basically in the middle ages Spain was ruled by the Muslim moors <span />
Older glaciers have "longer" ice crystals than younger glaciers. Glacier from where there is more snow falls than snow melts, over a period of years. It is then compacted into ice. The longer the glacier is the older it is.
