题目

As teenagers，you have many dreams．These dreams can be very big，such as winning the Nobel Prize，or they can be small．You may just want to become one of the ten best students in your class． Once you find a dream，what do you do with it? Do you ever try to make your dream real? “Follow Your Heart”by Australian writer Andrew Matthews tells us that making our dreams real is life’s biggest challenge． You may think you’re not very good at some school subjects，or that it is impossible for you to become a writer．These kinds of thoughts stop you from getting your dream，the 右图表示某种生态系统中4种成分之间的关系，以下相关叙述中正确的是(　　) A．甲和乙所包含的所有种群构成群落 B．乙1的同化量越大，流向乙2的能量就越少 C．丙不一定是原核生物 D．丁的含量增加将导致臭氧层被破坏