1.the presence of parasites in an animal will usually result in A.an increase in meiotic activity within structures of the host B.the inability of the host to maintain homeostasisC.the death of the host organism within twenty four hours D.an increase

1.the presence of parasites in an animal will usually result in A.an increase in meiotic activity within structures of the host B.the inability of the host to maintain homeostasisC.the death of the host organism within twenty four hours D.an increase
1.the presence of parasites in an animal will usually result in
A.an increase in meiotic activity within structures of the host
B.the inability of the host to maintain homeostasis
C.the death of the host organism within twenty four hours
D.an increase in genetic mutation rate in the host organism
2.a particular species of unicellular organism inhabits the intestines of termites,where the unicellular organisms are protected from predators.Wood that is ingested by the termites is digested by the unicellular organism,forming food for the termites.the relationship between these two species can be described as
A.harmful to both species
B.parasite / host
C.beneficial to both species
D.predator / prey
3.in a certain ecosystem,rattlesnakes are predators of prairie dogs.if the prairie dog population started to increase,how would the ecosystem most likely ragain stability?
A.the rattlesnake population would start to decrease.
B.the rattlesnake population would start to increase.
C.the prairie dog population would increase rapidly.
D.the prairie dog population would begin to prey on the rattlesnakes.
4.the size of a mouse population in a natural ecoystem tends to remain relatively constant to
A.the carrying capacity of the environment
B.the lack of natural predators
C.the cycling of energy
D.increase numbers of decomposers
1.___ 2.___ 3.___ 4.___
答案后面请加以说明为什么选这个答案(可以用中文解释).
做的一题得一题,做你们认为答案肯定的那个.
还有,请不要将以上的问题翻译了就给我.上面的问题我已经知道意思是什么了,所以你们不要直接将他翻译了就给我,

1.the presence of parasites in an animal will usually result in A.an increase in meiotic activity within structures of the host B.the inability of the host to maintain homeostasisC.the death of the host organism within twenty four hours D.an increase
1.D寄生者通常生活在寄主体内,它们从寄主那里获得物质,从而对寄主的适合度产生影响,但一般情况下,寄生者并不会导致寄主的死亡.寄生虫导致宿主繁殖能力的下降.密度制约在自由生活的动物种群中起着重要的调节作用,在寄生虫种群中密度制约的调节作用也不可忽视.密度制约可以通过调节寄生虫种群的出生率和死亡率等参数来影响宿主种群的增长,从而使宿主寄生虫系统达到一个相对稳定的平衡状态.在寄生关系形成的漫长历史过程中,对于寄生虫来说是如何适应新的寄主机体环境,而对于寄主来说是同寄生虫的斗争,通过这种适应与斗争的相互统一,而达到寄生关系的成立,其结果是适应和斗争本身客观上促使寄生虫与寄主的形态和机能都发生了改变.寄生虫和宿主之间是相互作用,相互影响,共同进化的,它们之间长期以来形成了一种稳定的,动态的平衡系统,共同维持着宿主寄生虫系统的平衡.所以寄生会促进寄主的遗传变异,协同进化.
2.C典型的互利共生,细菌得到保护,白蚁得到营养.
3.B当被捕食者的种群增加的时候,捕食者由于得到了更多的食物,捕食者种群数量会上升,直到由于被捕食者被大量捕食而种群数量下降.两者呈周期性波动.
4.A任何一种生物的种群数量取决于其生态环境条件,即环境的种群容纳量.