How does the immune system of vertebrates utilize a chemical concentration gradient?
a.The vertebrate immune system does not use chemical gradients.
b.The immune system releases chemical signals called chemokines, which create a chemical gradient that leukocytes use in migrating toward the infection site.
c.The immune system generates a gradient of reactive oxygen intermediates to increase the amount of toxic radicals and peroxides to combat invading pathogens.
d.The immune system produces thousands of histamines that act solely to create a histamine diffusion barrier.