If people tried to cross they would get shot
An "arms race".
diplomacy
It is true that the Mexican government encouraged settlement of Texas by Americans to create a buffer zone between the two countries.
The effectiveness of geographical barriers in promoting speciation is related to the extent of isolation they create between populations, which limits gene flow. Greater isolation increases the likelihood of genetic divergence between populations and the potential for speciation to occur. Other factors, such as the size of the populations and the duration of isolation, can also influence the effectiveness of geographical barriers in promoting speciation.
For a population to diverge, there must be factors that lead to genetic isolation or reproductive isolation between different groups within the population. This can be due to geographic barriers, different selective pressures, or mutations that create differences in traits. Over time, these isolated groups accumulate genetic and phenotypic differences, leading to divergence.
August 13 of 1961
The Pyrenees Mountains form the border between Spain, France, and Andorra.
An N-well in VLSI is a deep zone of highly N-type doped semiconductor, usually used to create reverse biased isolation junctions between components.
they prevented the colonists from trading with other foreign countries
create the Berlin Airlift and supply the city with food & fuel by plane from June 24th 1948 to May 11th, 1949
There's some confusion here. The Berlin Wall was built over eight years after Stalin's death ...
Natural selection leads to changes in a population over time as individuals with advantageous traits survive and reproduce, passing those traits to their offspring. If these changes accumulate and lead to reproductive isolation between populations, new species can form through a process called speciation. This can occur through geographical isolation, reproductive isolation, or genetic mutations that create barriers to interbreeding.