Passage 4
Questions 36 to 40 are based on the following passage.ª¥
The manner in which desert locust plagues develop is very complex.The two most important factors in that development are meteorology and the gregariousness of the insect.Since locusts breed most successfully in wet weather,rain in the semiarid regions inhabited by the desert locust provides ideal breeding conditions for a large increase in population.This increase must be repeated several times in neighboring breeding areas before enough locusts crowd together to form a swarm.As the supply of green,palatable food plants decreases to ward the end of the rainy season,the locusts become even more concentrated.They move on to other warm,damp,verdant places where they settle,feed,and reproduce.As this process is repeated a swarm eventually develops.Plagues are unpredictable and irregular because the meteorological patterns favorable to crowding are themselves irregular.
36.The passage deals primarily with desert locust swarms and their____ .
A)plaguesB)reproductionC)formationD)unpredictability

37.According to the author,which of the following is NOT an important factor in the growth of desert locust swarms?ª¤
A)An abundant food supply.
B)Large population increases.ª¤
C)Rain in the semiarid regions.
D)The gregarious nature of locusts.ª¤

38.According to the passage,a decrease in the number of palatable food plants causes ____ .ª¤
A)a decrease in the number of locusts
B)death to the local locust populationª¤
C)a heavier concentration of locusts
D)increased breeding of locustsª¤

39.It can be inferred from the passage that in periods of little or no rain the locust population becomes____ .ª¤
A)smallerB)denserC)more activeD)more unpredictableª¤

40.The next paragraph would most probably deal with ____.ª¤
A)the gregarious nature of locusts
B)rain patterns in the desertª¤
C)the type of food plants preferred by locusts
D)the control of locust plaguesª¤ª¤