The number of the bellbird in New Zealand got controlled by ______.

A．teachers should do as little as possible in helping students learn to read
B．teachers should encourage students to read as widely as possible
C．reading ability is something acquired rather than taught
D．reading is more complicated than generally believed

A．Advances in medical science made disease unable to regulate human population growth any longer in many parts of the world.
B．Medical cures have prolonged life but upset the reproductive age group by increasing many populations.
C．In Australia, the use of the myxomatosis virus hardly controlled the rabbit population with increasing resistance to the disease.
D．It is discovered all strains of virus can parasitize and kill the bacteria without harming the organism that the bacteria has infected.