Figure 44.5

-The wood duck shown in the above photograph was adversely affected by ____ and is making a comeback thanks to ____.  

A) global cooling; heat producing chemical added to their diet
B) sexually transmitted viruses; a new vaccine
C) limited numbers of natural cavities; artificial nesting boxes
D) high incidence of males being born; transplantation of females from other areas
E) invasive species; removal of introduced predators