The fact that astronomers have observed billions of stars clustered together is evidence that -- a. stars must have some sort of attraction for each other. b. all sections of space have the same numbers of stars. c. galaxies are probably older than the stars that make them up. d. the distance from one star to another varies, depending on the temperature of the star.

I know I am going out on a limb here but I think that the answer is D. I used process of elimination, C was definitely out, as well as A. I also know for sure that there are not the same amount of stars in all sections, you can't calculate that.

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

the answers are a and c