America's indigenous peoples were the first cultivators of what percentage of the crops grown in the world today?
a. 10
b. 30
c. 60
d. 80
Question 2
Over the course of our evolutionary history, most environmental stressors were climatic and geographic. Now, however:
a. humans have little environmental stressors, climatic or geographic.
b. nonhuman primates have more stressors than humans.
c. humans face a series of new environmental stressors of their own making.
d. humans also face daily weather stressors.
e. humans have climatic stress, but geographical stress has been removed because of technology.
Distribution of glaciers in North America (a) in the late twentieth century, and (b) 18,000 years ag
African farmers use chili peppers to ward elephants off their crops. Clever!
Madin-Darby canine kidney (MDCK) cells grown in specialized containers provide a
Large families on U.S. farms used to be common. Children helped plant and harvest crops, take care ...
Polar wandering paths for Eurasia and North America
Laboratory-Grown Stem Cells