Heat would best be transferred by conduction between

Since there are no options, I'm gonna take a guess and say your answer is Metal.

"Conduction is the transfer of heat between substances that are in direct contact with each other. The better the conductor, the more rapidly heat will be transferred. Metal is a good conduction of heat." (Source: https://www.edinformatics.com/math_science/how-is-heat-transferred.html)

dynamic equilibrium is the answer.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer