which of the following would have the best prepared native americans for the challenges of the colombian exhange? A. Access to sugar cane and other eouropean crops. B. immunity from smallpox and the flu C. the ability to shape iron into cookware and guns. D. the native populution and horses to be domesticated.

Often, a goby fish and a shrimp will live together in a burrow the shrimp has dug in the sand. the shrimp is almost blind and therefore is unable to see predators approaching when he is outside of the burrow. when the shrimp is in danger, the goby fish touches the shrimp with its tail to warn him. then, both go back into their burrow for safety. which type of relationship does this represent? a. mutualism b. parasitism c. commensalism d. predator/prey