Select the correct answer. Which is true regarding ac current? a. The electrons move back and forth. B. The +/- polarity is constant. C. It is common in portable devices. D. It can only produce low voltages.

Adult wasps sting caterpillars and inject their eggs into the caterpillars. the larvae feed on the caterpillars, leading to the death of the caterpillars. what kind of a relationship exists between the wasps and the caterpillars? a. the adult wasps are parasites to the caterpillars. b. the caterpillars are parasites to the wasps. c. the adult wasps are commensals, and the caterpillars are hosts. d. the caterpillars are commensals, and the adult wasps are hosts.