The human population on earth grew at an extraordinary rate during the 20th century, when it increased from 1.65 billion to 6 billion. what kind of curve would accurately show the changes in the human population during the 20th century? a. a life span curve b. an exponential curve c. a logistic curve d. a survivorship curve

The answer is B; exponential growth.   This is a phase of the S-shaped logistic curve of population growth that is characterized by a high birth rate and low death rate. The population doubles with each generation. Exponential growth is modeled by use of a J-shaped curve.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.