A 70-kg astronaut floating in space in a 110-kg mmu (manned maneuvering unit) experiences an acceleration of 0.029 m/s2 when he fires one of the mmu's thrusters.

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:

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.