Time in the AnimalWorld

Rhythm controlseverything in Nature._______(46)The sun provides a basic time rhythm for allliving creatures including humans.Nearly all animals are influenced by sun

cycles and havedeveloped a biological clock in their bodies following these cycles.The moonalso exerts its force and influence on the sea. Its gravitational attractioncauses

the rising of thetide._______(47)When the moon is behind the Earth,centrifugal force causes thesecond tide of the day.

Animals living intidal areas must have the instinct of predicting these changes,to avoid beingstranded and dying of dehydration.Since the time of the dinosaurs,the king crab

has been laying eggsat the seaside in a set way.To avoid predator fish,the eggs are always far fromseawater and protected by sand.In the following two months,the eggs

undergo dramaticchanges related to the cycles of the moon.When the second spring tide comes,theyoung king crabs have matured._______(48)

Most of themammals,either the giant elephant or the small shrew,have the same averagetotal number of heartbeats in their lifetime.Shrews live only for two and ahalf

years,and spendtheir life at a high speed and high tempo.Animals like shrews with a pulse rateof 600 per minute have an average total of eight hundred million heartbeats

throughout theirlife.The African elephant has a pulse rate of 25 beats per minute,and a lifespan of 60 years.The size of the body determines the speed of life._______(49)

As we get older,oursense of time is being influenced by the physiological changes of our body.Theelderly spend more time resting,and do few sports._______(50)For a

child,a week is seenas a long time._________（49）

A.For an adult,timegoes fast year by year.

B.It controls,forexample,the flapping of birds' wings,the beating of the heart and the risingand setting of the sun.

C.The larger theanimal is,the longer its life span is and the slower its life tempo is.

D.The tide goes outwhen the moon moves away and its attraction is weaker.

E.We always tend tothink all the animals have the same sense of time as human beings.