Which of the following statements about galaxies is true? a. galaxies typically contain millions of stars. b. galaxies actually contain very few stars. c. galaxies typically contain thousands of stars. d. galaxies typically contain billions of stars.

the answer is D i took the quiz so it is definitely D  

D. Galaxies typically contain billions of stars.

Explanation:

A galacy on average contains from 150-250 billion up to 100 trillion of starts, for example the milky way has aproximately 200 billion stars, there are for example andromeda galaxy has approximately 1 trillion stars but the largest observable and found galaxy in the universe is IC1101 has a mass of 100 trillion stars and this is only what we have been able to observe.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

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: