Question

Why cannot we breath and swallow at same time

Answer 1

Their is a part in our body which is called  $\textbf{epiglottis}$, this is the main responsible part which is responsible to avoid entering the food in wind pipe.

$\textbf{How it works?  }$

When we swallow food, this epiglottis covers up the mouth of respiratory tract/wind pipe, this don't allow food to enter the food to both respiratory tract and food tract at the same time.