Ecology that focuses on dynamic changes occurring in one species is ecology. 1) population 2) applied 3)systems

1) population

Explanation:

Ecology of population is a sub-discipline of ecology that concerns with the dynamics of population of the species, interaction of the population with the environment, with other species and among members of the same species. It studies how size of the population change over area and time.  

Therefore, on the basis of the above description, ecology that focuses on dynamic changes occurring in one species is called as population ecology.

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added