Galileo proved that objects fall at the same time through his Leaning Tower of Pisa experiment but we see that a feather clearly falls slower than a ball of steel and a falling human is another case entirely! So, objects fall at the same time, no matter their weight, is the only thing that makes things fall differently, air?

Explanation:

The rate at which a body falls is independent of it's mass. The larger body has inertia which makes it resistance to being accelerate. The smaller gets pullled by the gravity. The two effects cancel out each other.

Objects of different mass would fall at the same time provided that they both experience the same air resistance.

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation:

when it gains or loses electrons