How efficient is a machine that does 84 ) worth of work, assuming that you put in 112J worth of work?

Which would not reduce the amount of green house gasses in the air

In which situation has the independent variable for the experiment been changed? check all that apply. changed from counting the number of duckweed at day 0 and day 14 to counting them every day changed from testing duckweed growth in beakers to testing duckweed growth in large outdoor tanks changed from testing the effect of ph on duckweed growth to testing the effect of light levels on duckweed growth changed from testing the effect of acid ph on duckweed growth to testing the effect of basic ph on duckweed growth

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.