which of the following mostly accurately describes why a plastic, air-filled ball expands in the sun?
a) when they heat up the air molecules expand
b) when they heat up molecules making up air expand
c) when they heat up, the distance between the air molecules expands.
d) when they heat up the distance between the molecules making up the air expands.

This is a tricky one, especially if English is not your first language.

It was not the first language of the question writer either, since none of the answer sentences are in correct English.

 

However we do not do all the work so can you tell me a little about each.

 

a) do the molecules themselves expand?

 

b) Is there any difference between answer (a) and answer (b) ?

 

c) Tell me, in your own words, what happens when the balloon of air heats up.

 

d) Is there any difference between answer © and answer (d) ?

Edited June 5, 201312 yr by studiot

It was not the first language of the question writer either, since none of the answer sentences are is in correct English.

Good catch, John Cuthber, but how does that help the OP?