Some horse ancestors had limb characteristics that were similar to what we see in the modern horse. Which of the following best describes the evolution of horse limbs over time?

a
Over time, the horse limb gained footbones.
b
Over time, the horse limb got longer.
c
Over time, the horse limb became shorter.
d
Over time, the horse limb grew wider.

b - Over time, the horse limb got longer.