Question

Which of the following was a key obstacle that hominins' increase in brain size had to overcome?

a-the challenges of walking with a head that is too heavy
b-overcoming the trend of ever more self-sufficient children eager to separate themselves from their mothers
c-overcoming the trend of clumsy locomotion that makes hominins vulnerable to predators
d-larger skulls demanding more elastic birth canals, even though the requirements of skeletal development during a woman's lifetime limit the elasticity of birth canals
e-larger skulls demanding larger birth canals, even though the requirements of upright bipedalism impose limits on the expansion of the human pelvic opening

Answer 1

The key obstacle that hominins had to overcome in relation to the increase in brain size was the demand for larger birth canals while still maintaining the requirements of upright bipedalism.

Step-by-step explanation:

The key obstacle that hominins had to overcome in relation to the increase in brain size was larger skulls demanding larger birth canals, even though the requirements of upright bipedalism impose limits on the expansion of the human pelvic opening. This means that the size of the birth canal was limited by the need for upright walking, while the larger skulls required larger birth canals.