Whether a planet has an atmosphere or not depends on a number of factors: mass, temperature, composition of the crust, volcanic activity, and complex evolutionary processes.
rank the planets according to how well they retain their atmospheres, using the following criteria:
a. the planet that still maintains its primary atmosphere, ranks first.
b. the planet that lost its primary atmosphere but retains a dense secondary atmosphere, ranks second.
c. the planet that lost its primary atmosphere and retains a tenuous secondary atmosphere, ranks third.
d. the planet that retained neither its primary nor secondary atmospheres, ranks last.

The respiratory system removes oxygen and water from the body. select the best answer from the choices provided t f

The sound level near a noisy air conditioner is 70 db. if two such units operate side by side, the sound level near the, would bea. 70dbb. 73 dbc. 105 dbd 140 db

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.