Explain if the efficiency of a machine can ever be greater than 100%?

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Which statement best describes the function of enzymes?

Pastoral farming is best described as a. a method of raising livestock and moving herds b. an african method of agriculture c. a method of cultivating crops on poor soils d. a common method of desert farming select the best answer from the choices provided a b c d