What causes a nuclear fission chain reaction to continue?
A - the energy that results from the previous fission reaction
B - thermal energy added to the system from the surroundings
C - thermal energy released from the system to the surroundings
D - the neutrons that result from the previous fission reaction

D

Explanation:

The emission of several neutrons in the fission process leads to the possibility of a chain reaction if at least one of the fission neutrons induces fission in another fissile nucleus, which in turn fissions and emits neutrons to continue the chain.

I hope this is right LOL

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.