a drought
Famine
Competition between organisms would most likely cause the phenotype frequency in a population that changes each generation.
a decrease in habitats due to human development or natural disasters
Birth Control is what is most likely to limit human population growth.
environmental geographer
Which would most likely decrease the genetic variation in the human population?
Decrease.
alternately increase and decrease
Cooling.
reproduce
decrease the number of hawks
Extinction is most likely to be caused by environmental conditions. Dramatic changes to the climate can mean that species are no longer adapted to survive.
Famine
Sudden changes in environmental conditions.
The aliens start attacking them more
The population will become extinct.
Three changes are probably global temperature change(Ice Age,NOW), and...nothing else. This is most likely the only environmental change that affects evolution.