The weeds in your garden have developed a resistance to the herbicide you use. Why did this occur? a. cloning
b. genetic engineering
c. natural selection
d. selective breeding

Wjat are substances intentionally added to food to produce a desired effect?

If something is painful during exercise, what should you do? a. back off the exercise. b. modify the exercise. c. consult a physician if the pain persists. d. all of the above

When exercising, you shouldn’t go past to avoid an injury.