Tim Birkhead and his colleagues were able to boost the immune systems of male zebra finches and increase their attractiveness to females by
A) enlarging their tails.
B) injecting them with hormones.
C) feeding them carotenoid pigments.
D) increasing their caloric intake.
E) injecting them with phytohemagglutinin.

Question

Quizplus · Accepted Answer

Tim Birkhead and his colleagues were able to boost the immune systems of male zebra finches and increase their attractiveness to females by feeding them carotenoid pigments. Carotenoids are known to have immunostimulatory effects and are responsible for the bright coloration of many animals.

Tim Birkhead and His Colleagues Were Able to Boost the Immune