Answer:
Epinephrine, also known as Adrenaline
Explanation:
Adrenaline impacts short-term mood and can take seconds to flood your system.
*it may also be cortisol, I'm not sure if there's more context. Cortisol takes longer to work and can have long-term effects.
Answer:
Addition of a(n) methyl group to certain lysine residues of a histone protein makes the region of chromatin transcriptionally silent; addition of a(n) acetyl group to certain lysine residues makes the region of chromatin transcriptionally active.
Explanation:
The changes suffered in the expression and activity of the genes are studied by the Epigenetics.
