A trading arrangement that eliminates most or all barriers to trade among participating nations and utilizes common barriers to trade with other countries outside the group is called a

preferential trade agreement

Explanation:

This agreement is known as a preferential trade agreement. It is called this because it tends to make it easier for specific goods to be traded but only to the countries that are part of the group and/or agreement. This agreement also makes it harder for countries that are not part of the agreement to be able to trade with the countries that are in order to maintain the countries within the agreement trading with each other.

ans.

heterothermic organisms include those organisms that can switch between homeothermic (having body temperature higher than environment) and poikilothermic (having variation in internal body temperature) strategies.

some migratory birds show heterothermy as they decrease their metabolic rate during cold nights to keep their body temperature low. drop in metabolic rate allows increase in production efficiency of birds that reduces the internal body temperature to make it equal to external cold temperature during cold nights.

thus, the correct answer is 'birds allow their temperature drop in order to increase their production efficiency.'

the answer is true.  i do believe this is the answer because of the amount of wrecks people get into each year.  if you double this with avoiding those so said wrecks, that would make you a "skilled" driver.