Question

why newborns are unable to hold their head and to walk?

why is possible the repolarizacion of the neuron?

Answer 1

WHY THE NEWBORN BABIES CAN’T WALK AND HOLD THEM UP WHILE THIS IS NOT SIMILAR IN CASE ON ANIMALS

Human infants are born with underdeveloped brains, and it takes some after birth until their brains have matured to the point that walking, climbing, etc. are possible.

Our hips are smaller, and turned at an angle that is better for walking upright, and our craniums are larger to accomodate our bigger brains.

This means that a human infant with a fully developed brain would have much to massive a head to pass through the average human birth canal. So, babies are born with smaller heads, but with incomplete brains, making the infant rely heavily on its parents for early survival.

One of the first traits that differentiated humans from our ancestors was upright gait. There are several hypotheses about the emergence of this trait, but it seems to have offered a way to move more efficiently in open environments such as the savanna. Their upright gait had changed their pelvis to look much like our modern one. This reshaped pelvis came with a narrower birth canal, making childbirth more difficult.

As it turned out, the evolutionary answer was to let the brain keep growing outside the womb before it matures. So in contrast to other mammals, humans have a good bit of development to do after birth.

This is a result of relatively undeveloped infant who needs lots of care and can do much less for itself than other newborn primates.