If we look at the drug OxyContin we can see that if someone has built a tolerance two things would occur their current dose would leave them feeling as if they need more and the tolerance could lead to abuse in order to get the pain relieving benefits. Withdrawal are the effects that happen when someone builds a tolerance. These symptoms could include dizziness, nausea, clammy skin, etc. The medication user might have built a tolerance and is feeling the effects of withdrawal because they need more of the medication for it to have an effect on their pain levels as well as reduce the withdrawal symptoms. Withdrawal is the bodies response to no longer having the medication consistently equal in the blood brain exchange.
Well for starters, they do not have leaves which reduces transpiration. They also grow really long roots that can absorb the smallest traces of moisture in the earth.