When is the lac operon most active? a: when glucose levels are high and lactose is present . b: when glucose levels are low and lactose is absent . c: when glucose levels are low and lactose is present . d: when glucose levels are high and lactose is absent?

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.

answer; both surfaces of the membrane are nonpermeable

the potatoes have high sugar concentrations and although these potatoes were different we could seethe effects that their sugar concentrations had in different environments. for example, the potatoes in sample a, were placed in pure water. this created a hypertonic environment and caused the potatoes to draw in water from its surroundings. we saw the opposite happen with the potatoes in sample b when placed in the sodium chloride solution. the potatoes in this case were in a hypotonic solution and therefore lost water to their surroundings.