Which of the following is true of gases?
a) gases are not easily compressed because of expansion and limited space between particles.
b) gases mix easily because of their high kinetic energy and low intermolecular forces.
c) gas particles diffuse easily because of their low fluidity and high intermolecular forces.
d) gas particles spread out to fill a container because of their high density and high kinetic energy.

It decreases by 4 is your answer mark brainliest 

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.