Outside of the U.S., many cruise lines do not have automatic tipping policies, says McDaniel, as other countriesâ tipping customs are different than ours (and thus their staff is paid differently), so it may pay to look at cruises leaving from other countries and then look at their âsuggestedâ tipping options.
Best Answer: Active transport is the mediated process of moving particles across a biological membrane against a concentration gradient. If the process uses chemical energy, such as from adenosine triphosphate (ATP), it is termed primary active transport. Secondary active transport involves the use of an electrochemical gradient.
A common example of active transport, or moving a substance against its gradient, is the maintaining of a balance of sodium and potassium inside and outside a cell. Obviously too much sodium inside the cell would cause cell death. So, the cell must actively regulate how much sodium is allowed in through the membrane.