Is a loaf of bread a variable or fixed cost for a supermarket?

For what reason might an inmate be granted a furlough

Why are the majority of the world's economies mixed? what may happen to the "pure" types of economies (traditional, socialist/command, market capitalist) when they incorporate elements from other economic models?

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