role of a board of directors in a non profit The rubber hose in the engine compartment will be used for a long time and it will be a problem for older vehicles. Once aging, gasoline can leak into the engine compartment. The air conditioning system will allow the smell of petrol to enter the car. Therefore, once the rubber tube is old, need to change promptly! The response to variability is a resilient instinct. Elastic instinct (also called the conditioned reflex) is an organism formed in the process of life change with conditions and reflection, under certain conditions unrelated stimulus be signals caused by reflections of the unconditioned stimulus. It is not innate, but the reflection of the organism under certain conditions under certain conditions. Conditioned reflex can make animal learning and memory and non-conditional reflex related, but completely different new reflection activity. The formation of conditioned reflex is the formation or connection of the cerebral cortex, which is based on non-conditioned reflex. With conditioned reflex, animals not only reflect things that have direct physiological meaning, but also those that have indirect physiological significance. Elastic instinct can make animals for the changed things to adjust their instinctive behavior, make it easy to adapt to changes in the environment, thus than rigid instinct has more flexibility and purpose, and the body through the conditioning can not before the arrival of the stimulus itself accordingly reaction, make the body more proactive and initiative. Anyway, elastic instinct is higher biological value of variability of external things more advanced way of ordering reaction, is on the rigid instinct, extension, and the synthesis, make rigid instinct has more purposeful and flexibility Money supply is determined by the central bank of exogenous variables, the demand for money depends on the liquidity preference of people, when people's liquidity preference to enhance tend to increase the money hold, so rates are determined by the liquidity preference in joint decision currency demand and currency supply; Loanable ZiJinLun combines the first two interest rate determinism, that interest rate is determined by the supply and demand of loanable funds, including the total savings and new bank money supply and demand including the total investment and new currency demand, interest rate decision depends on common commodity market and money market equilibrium Accounting earnings include only realized gains, and exclude unrealized gains and losses, the economic benefits will be enterprise's operating earnings and are favorable to the same treatment, regardless of whether they have been implemented. Thus, in general, accounting gains are less than economic gains, and the difference is mainly in the interest. New participants in the education blockchain ecosystem There is no risk of this arbitrage. Range and once the two currencies yield, the yield of arbitrage mechanism will make two currencies are equal, that is, different interest rates in the currency of the country there is inherently a trend towards an equalization and trend, it is the interest rate index key aspects of the impact of foreign exchange to, also is our interpretation and grasp the key interest rate index.